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<!--Created on: 3/7/2019 2:15:47 PM-->
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_AvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStock" xlink:label="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStock" xlink:to="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Stock and Federal Reserve Bank Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Chicago ("FHLBC") and Federal Reserve Bank Chicago ("FRBC") stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FHLBC and FRBC Stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableHeldForSaleAmount" xlink:label="us-gaap_LoansReceivableHeldForSaleAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansReceivableHeldForSaleAmount" xlink:to="us-gaap_LoansReceivableHeldForSaleAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansReceivableHeldForSaleAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans Held-For-Sale, Other, not Part of Disposal Group or Discontinued Operation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansReceivableHeldForSaleAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans held-for-sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:label="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome" xlink:to="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Net of Deferred Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel" xlink:label="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total Loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveTerseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">PCI loans, net of purchase accounting adjustments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total Loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowance" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivableAllowance" xlink:to="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Allowance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Beginning Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Less: allowance for loan losses</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivableNetReportedAmount" xlink:to="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Net Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LoansAndLeasesReceivableNetReportedAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentNet" xlink:label="us-gaap_PropertyPlantAndEquipmentNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentNet" xlink:to="us-gaap_PropertyPlantAndEquipmentNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property, Plant and Equipment, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Premises and equipment, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Book Value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateAcquiredThroughForeclosure" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateAcquiredThroughForeclosure" xlink:to="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Acquired Through Foreclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Balance at end of period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Balance at beginning of period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other real estate owned</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_RealEstateAcquiredThroughForeclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Carrying value of other real estate owned</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ServicingAssetAtFairValueAmount" xlink:label="us-gaap_ServicingAssetAtFairValueAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ServicingAssetAtFairValueAmount" xlink:to="us-gaap_ServicingAssetAtFairValueAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ServicingAssetAtFairValueAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Servicing Asset at Fair Value, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel" xlink:label="us-gaap_ServicingAssetAtFairValueAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage servicing rights, fair value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ServicingAssetAtFairValueAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage servicing rights, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ServicingAssetAtFairValueAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage servicing rights</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IntangibleAssetsNetIncludingGoodwill" xlink:to="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Intangible Assets, Net (Including Goodwill)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IntangibleAssetsNetIncludingGoodwill_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Goodwill and core deposit intangible</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BankOwnedLifeInsurance" xlink:label="us-gaap_BankOwnedLifeInsurance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BankOwnedLifeInsurance" xlink:to="us-gaap_BankOwnedLifeInsurance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Bank Owned Life Insurance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Bank-owned life insurance (BOLI)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_BankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Bank-owned life insurance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxAssetsNet" xlink:to="us-gaap_DeferredIncomeTaxAssetsNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Assets, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredIncomeTaxAssetsNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred tax assets, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherAssets" xlink:label="us-gaap_OtherAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherAssets" xlink:to="us-gaap_OtherAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Assets.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Assets" xlink:label="us-gaap_Assets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Assets" xlink:to="us-gaap_Assets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Assets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_Assets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAbstract" xlink:label="us-gaap_LiabilitiesAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAbstract" xlink:to="us-gaap_LiabilitiesAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Liabilities [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LiabilitiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Liabilities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepositsAbstract" xlink:label="us-gaap_DepositsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepositsAbstract" xlink:to="us-gaap_DepositsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DepositsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposits [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DepositsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposits:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestBearingDepositLiabilities" xlink:label="us-gaap_NoninterestBearingDepositLiabilities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoninterestBearingDepositLiabilities" xlink:to="us-gaap_NoninterestBearingDepositLiabilities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest-bearing Deposit Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest bearing demand</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_NoninterestBearingDepositLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest bearing deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositLiabilitiesAbstract" xlink:label="us-gaap_InterestBearingDepositLiabilitiesAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestBearingDepositLiabilitiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest-bearing Deposit Liabilities [Abstract]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherLiabilities" xlink:to="us-gaap_OtherLiabilities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other liabilities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Liabilities" xlink:label="us-gaap_Liabilities" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Liabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_Liabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total liabilities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="us-gaap_StockholdersEquityAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockholdersEquityAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stockholders' Equity</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockValue" xlink:to="us-gaap_CommonStockValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Common stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="us-gaap_AdditionalPaidInCapital" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Accumulated other comprehensive (loss) income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockCommonValue" xlink:label="us-gaap_TreasuryStockCommonValue" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TreasuryStockCommonValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Treasury Stock, Common, Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_TreasuryStockCommonValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Treasury stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquity" xlink:label="us-gaap_StockholdersEquity" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquity" xlink:to="us-gaap_StockholdersEquity_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_StockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_StockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_StockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total stockholders' equity</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAndStockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Liabilities and Equity</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestAndDividendIncomeOperatingAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest and Dividend Income</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest and Fee Income, Loans and Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestAndFeeIncomeLoansAndLeases_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans, including fees</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestAndFeeIncomeLoansHeldForSaleMortgages_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans held-for-sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract" xlink:label="us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest and Dividend Income, Securities, by Taxable Status [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestAndDividendIncomeSecuritiesByTaxableStatusAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities:</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestIncomeSecuritiesTaxable" xlink:to="us-gaap_InterestIncomeSecuritiesTaxable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestIncomeSecuritiesTaxable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Income, Securities, Operating, Taxable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestIncomeSecuritiesTaxable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Taxable</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestIncomeSecuritiesTaxExempt_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax exempt</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DividendIncomeOperating_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividend Income, Operating</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DividendIncomeOperating_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividends from FHLBC and FRBC stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeDepositsWithFinancialInstitutions" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Income, Deposits with Financial Institutions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestIncomeDepositsWithFinancialInstitutions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest bearing deposits with financial institutions</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest and Dividend Income, Operating</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestAndDividendIncomeOperating_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net interest income</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestExpenseNOWAccountsMoneyMarketAccountsAndSavingsDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Savings, NOW, and money market deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseTimeDeposits" xlink:label="us-gaap_InterestExpenseTimeDeposits" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestExpenseTimeDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time deposits</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestExpenseSubordinatedNotesAndDebentures_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Expense, Subordinated Notes and Debentures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestExpenseSubordinatedNotesAndDebentures_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subordinated debt</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_InterestExpenseNotesPayableAndOtherBorrowings" xlink:label="osbc_InterestExpenseNotesPayableAndOtherBorrowings" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_InterestExpenseNotesPayableAndOtherBorrowings" xlink:to="osbc_InterestExpenseNotesPayableAndOtherBorrowings_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_InterestExpenseNotesPayableAndOtherBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the interest expense on notes payable and other borrowings.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_InterestExpenseNotesPayableAndOtherBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Expense Notes Payable And Other Borrowings</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_InterestExpenseNotesPayableAndOtherBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Notes payable and other borrowings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpense" xlink:label="us-gaap_InterestExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestExpense" xlink:to="us-gaap_InterestExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_InterestExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total interest expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeExpenseNet" xlink:label="us-gaap_InterestIncomeExpenseNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestIncomeExpenseNet" xlink:to="us-gaap_InterestIncomeExpenseNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Income (Expense), Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_InterestIncomeExpenseNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net interest and dividend income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProvisionForLoanAndLeaseLosses" xlink:label="us-gaap_ProvisionForLoanAndLeaseLosses" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProvisionForLoanAndLeaseLosses" xlink:to="us-gaap_ProvisionForLoanAndLeaseLosses_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProvisionForLoanAndLeaseLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision for Loan and Lease Losses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProvisionForLoanAndLeaseLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision for loan and lease losses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProvisionForLoanAndLeaseLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision (release)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss" xlink:to="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Income (Expense), after Provision for Loan Loss</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_InterestIncomeExpenseAfterProvisionForLoanLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net interest and dividend income after provision for loan and lease losses</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncomeAbstract" xlink:label="us-gaap_NoninterestIncomeAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoninterestIncomeAbstract" xlink:to="us-gaap_NoninterestIncomeAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoninterestIncomeAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest Income [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NoninterestIncomeAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest Income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax" xlink:to="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fees and Commissions, Depositor Accounts</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RevenueFromContractWithCustomerIncludingAssessedTax_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Service charges on deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageServicingRightsMSRImpairmentRecovery" xlink:label="us-gaap_MortgageServicingRightsMSRImpairmentRecovery" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MortgageServicingRightsMSRImpairmentRecovery" xlink:to="us-gaap_MortgageServicingRightsMSRImpairmentRecovery_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MortgageServicingRightsMSRImpairmentRecovery_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Servicing Rights (MSR) Impairment (Recovery)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_MortgageServicingRightsMSRImpairmentRecovery_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage servicing rights mark to market loss</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MortgageServicingRightsMSRImpairmentRecovery_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Change in fair value of mortgage servicing rights</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainLossOnSaleOfMortgageLoans" xlink:label="us-gaap_GainLossOnSaleOfMortgageLoans" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GainLossOnSaleOfMortgageLoans" xlink:to="us-gaap_GainLossOnSaleOfMortgageLoans_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GainLossOnSaleOfMortgageLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gain (Loss) on Sale of Mortgage Loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_GainLossOnSaleOfMortgageLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net gain on sales of mortgage loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GainLossOnSaleOfMortgageLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net gain on sales of mortgage loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_GainLossOnSaleOfMortgageLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gain on sale of loan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtAndEquitySecuritiesGainLoss" xlink:label="us-gaap_DebtAndEquitySecuritiesGainLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtAndEquitySecuritiesGainLoss" xlink:to="us-gaap_DebtAndEquitySecuritiesGainLoss_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtAndEquitySecuritiesGainLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gain (Loss) on Sale of Securities, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_DebtAndEquitySecuritiesGainLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities (gains) losses, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtAndEquitySecuritiesGainLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities gains (losses), net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BankOwnedLifeInsuranceIncome" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BankOwnedLifeInsuranceIncome" xlink:to="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Bank Owned Life Insurance Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase in cash surrender value of BOLI</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BankOwnedLifeInsuranceIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase in cash surrender value of BOLI</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeathBenefitRealizedOnBankOwnedLifeInsurance" xlink:label="osbc_DeathBenefitRealizedOnBankOwnedLifeInsurance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeathBenefitRealizedOnBankOwnedLifeInsurance" xlink:to="osbc_DeathBenefitRealizedOnBankOwnedLifeInsurance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeathBenefitRealizedOnBankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the death benefit realized from bank owned life insurance during the reporting period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeathBenefitRealizedOnBankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Death Benefit Realized on Bank Owned Life Insurance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeathBenefitRealizedOnBankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Death benefit realized on bank-owned life insurance</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CardInterchangeIncomeDebit" xlink:label="osbc_CardInterchangeIncomeDebit" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CardInterchangeIncomeDebit" xlink:to="osbc_CardInterchangeIncomeDebit_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CardInterchangeIncomeDebit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income earned from debit card services for the reporting period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CardInterchangeIncomeDebit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Card Interchange Income Debit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CardInterchangeIncomeDebit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debit card interchange income</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate" xlink:label="osbc_GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate" xlink:to="osbc_GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the gain (loss) on disposal of fixed assets and transfer of property to other real estate during the reported period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gain Loss On Disposal Of Fixed Assets And Transfer Of Property To Other Real Estate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gains (losses) on disposal and transfer of fixed assets, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncomeOtherOperatingIncome" xlink:label="us-gaap_NoninterestIncomeOtherOperatingIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoninterestIncomeOtherOperatingIncome" xlink:to="us-gaap_NoninterestIncomeOtherOperatingIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoninterestIncomeOtherOperatingIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest Income, Other Operating Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NoninterestIncomeOtherOperatingIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestIncome" xlink:label="us-gaap_NoninterestIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoninterestIncome" xlink:to="us-gaap_NoninterestIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoninterestIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NoninterestIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total noninterest income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestExpenseAbstract" xlink:label="us-gaap_NoninterestExpenseAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoninterestExpenseAbstract" xlink:to="us-gaap_NoninterestExpenseAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoninterestExpenseAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest Expense [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NoninterestExpenseAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest Expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LaborAndRelatedExpense" xlink:label="us-gaap_LaborAndRelatedExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LaborAndRelatedExpense" xlink:to="us-gaap_LaborAndRelatedExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LaborAndRelatedExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Labor and Related Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LaborAndRelatedExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Salaries and employee benefits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquipmentExpense" xlink:label="us-gaap_EquipmentExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquipmentExpense" xlink:to="us-gaap_EquipmentExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EquipmentExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equipment Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EquipmentExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Occupancy, furniture and equipment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommunicationsAndInformationTechnology" xlink:label="us-gaap_CommunicationsAndInformationTechnology" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommunicationsAndInformationTechnology" xlink:to="us-gaap_CommunicationsAndInformationTechnology_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommunicationsAndInformationTechnology_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Communications and Information Technology</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommunicationsAndInformationTechnology_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Computer and data processing</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalDepositInsuranceCorporationPremiumExpense" xlink:label="us-gaap_FederalDepositInsuranceCorporationPremiumExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FederalDepositInsuranceCorporationPremiumExpense" xlink:to="us-gaap_FederalDepositInsuranceCorporationPremiumExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FederalDepositInsuranceCorporationPremiumExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Deposit Insurance Corporation Premium Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FederalDepositInsuranceCorporationPremiumExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FDIC insurance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GeneralInsuranceExpense" xlink:label="us-gaap_GeneralInsuranceExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GeneralInsuranceExpense" xlink:to="us-gaap_GeneralInsuranceExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GeneralInsuranceExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">General Insurance Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GeneralInsuranceExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">General bank insurance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfIntangibleAssets" xlink:label="us-gaap_AmortizationOfIntangibleAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AmortizationOfIntangibleAssets" xlink:to="us-gaap_AmortizationOfIntangibleAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of Intangible Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of core deposit intangible</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_AmortizationOfIntangibleAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of core deposit intangible</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdvertisingExpense" xlink:label="us-gaap_AdvertisingExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdvertisingExpense" xlink:to="us-gaap_AdvertisingExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AdvertisingExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Advertising Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AdvertisingExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Advertising expense</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DebitCardInterchangeExpense" xlink:label="osbc_DebitCardInterchangeExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DebitCardInterchangeExpense" xlink:to="osbc_DebitCardInterchangeExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DebitCardInterchangeExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This element represents the debit card interchange expense.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DebitCardInterchangeExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debit Card Interchange Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DebitCardInterchangeExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debit card interchange expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LegalFees" xlink:label="us-gaap_LegalFees" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LegalFees" xlink:to="us-gaap_LegalFees_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LegalFees_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Legal Fees</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LegalFees_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Legal fees</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OtherRealEstateOwnedExpense" xlink:label="osbc_OtherRealEstateOwnedExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OtherRealEstateOwnedExpense" xlink:to="osbc_OtherRealEstateOwnedExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OtherRealEstateOwnedExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This element represents the other real estate owned expense during the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OtherRealEstateOwnedExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Real Estate Owned Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OtherRealEstateOwnedExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other real estate expense, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherNoninterestExpense" xlink:label="us-gaap_OtherNoninterestExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherNoninterestExpense" xlink:to="us-gaap_OtherNoninterestExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherNoninterestExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Noninterest Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherNoninterestExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NoninterestExpense" xlink:label="us-gaap_NoninterestExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NoninterestExpense" xlink:to="us-gaap_NoninterestExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NoninterestExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Noninterest Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NoninterestExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total noninterest expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income (Loss) from Continuing Operations before Equity Method Investments, Income Taxes, Extraordinary Items, Noncontrolling Interest</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income before income taxes</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income (loss) before income taxes and equity in undistributed net income of subsidiaries</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="us-gaap_IncomeTaxExpenseBenefit" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxExpenseBenefit" xlink:to="us-gaap_IncomeTaxExpenseBenefit_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Tax Expense (Benefit)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision for income taxes</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total income tax expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_IncomeTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income tax benefit</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Income (Loss) Available to Common Stockholders, Basic</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net income available to common stockholders</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="us-gaap_EarningsPerShareBasic" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareBasic" xlink:to="us-gaap_EarningsPerShareBasic_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Earnings Per Share, Basic</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EarningsPerShareBasic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Basic earnings per share (in dollars per share)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="us-gaap_EarningsPerShareDiluted" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareDiluted" xlink:to="us-gaap_EarningsPerShareDiluted_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Earnings Per Share, Diluted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EarningsPerShareDiluted_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Diluted earnings per share (in dollars per share)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockDividendsPerShareDeclared" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockDividendsPerShareDeclared" xlink:to="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Common Stock, Dividends, Per Share, Declared</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockDividendsPerShareDeclared_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividends declared per share (in dollars per share)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:label="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract" xlink:to="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementOfIncomeAndComprehensiveIncomeAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Consolidated Statements of Comprehensive Income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLoss" xlink:label="us-gaap_NetIncomeLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLoss" xlink:to="us-gaap_NetIncomeLoss_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Income (Loss) Attributable to Parent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetIncomeLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net income</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfCashFlowsAbstract" xlink:to="us-gaap_StatementOfCashFlowsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementOfCashFlowsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Consolidated Statements of Cash Flows</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Cash Provided by (Used in) Operating Activities, Continuing Operations [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash flows from operating activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash Flows from Operating Activities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:to="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Adjustments to reconcile net income to net cash provided by (used in) operating activities:</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Adjustments to reconcile net income (loss) to net cash from operating activities:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:label="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments" xlink:to="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Accretion (Amortization) of Discounts and Premiums, Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_AccretionAmortizationOfDiscountsAndPremiumsInvestments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net premium amortization/discount (accretion) on securities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale" xlink:label="us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale" xlink:to="us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments for Origination of Mortgage Loans Held-for-sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsForOriginationOfMortgageLoansHeldForSale_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Originations of loans held-for-sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfLoansHeldForSale" xlink:label="us-gaap_ProceedsFromSaleOfLoansHeldForSale" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfLoansHeldForSale" xlink:to="us-gaap_ProceedsFromSaleOfLoansHeldForSale_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromSaleOfLoansHeldForSale_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from Sale of Loans Held-for-sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromSaleOfLoansHeldForSale_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from sales of loans held-for-sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProceedsFromSaleOfLoansHeldForSale_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from sale of loan to investors</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans" xlink:label="osbc_NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans" xlink:to="osbc_NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of net discount accretion of purchase accounting adjustment on loans.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Discount Accretion Of Purchase Accounting Adjustment On Loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net discount (accretion)/premium amortization of purchase accounting adjustment on loans</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance" xlink:label="osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance" xlink:to="osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The net gain (loss) before provision for valuation allowances resulting from sales and other disposals of other real estate owned.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gains Losses On Sales Of Other Real Estate Before Provision For Valuation Allowance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gain on sales, net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net gains on sale of other real estate owned</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateOwnedValuationAllowanceProvision1" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceProvision1" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateOwnedValuationAllowanceProvision1" xlink:to="us-gaap_RealEstateOwnedValuationAllowanceProvision1_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceProvision1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Owned, Valuation Allowance, Provision</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceProvision1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision for other real estate owned valuation losses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceProvision1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision for unrealized losses</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepreciationDepletionAndAmortization" xlink:label="us-gaap_DepreciationDepletionAndAmortization" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepreciationDepletionAndAmortization" xlink:to="us-gaap_DepreciationDepletionAndAmortization_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DepreciationDepletionAndAmortization_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Depreciation, Depletion and Amortization</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DepreciationDepletionAndAmortization_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Depreciation of fixed assets and amortization of leasehold improvements</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:label="us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GainLossOnSaleOfPropertyPlantEquipment" xlink:to="us-gaap_GainLossOnSaleOfPropertyPlantEquipment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GainLossOnSaleOfPropertyPlantEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gain (Loss) on Disposition of Property Plant Equipment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_GainLossOnSaleOfPropertyPlantEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net (gains) / losses on disposal and transfer of fixed assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:label="us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable" xlink:to="us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase (Decrease) in Income Taxes Payable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Change in current income taxes receivable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_IncreaseDecreaseInAccruedIncomeTaxesPayable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Change in taxes payable</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of deferred tax expense benefit after deferred tax asset valuation adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense Benefit After Deferred Tax Asset Valuation Adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision for deferred tax expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net deferred tax expense due to DTA revaluation</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment" xlink:label="osbc_DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment" xlink:to="osbc_DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of deferred tax assets, net deferred tax expense, valuation adjustment.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Assets, Net Deferred Tax Expense, Valuation Adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net deferred tax expense due to DTA valuation adjustment</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets" xlink:label="osbc_IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets" xlink:to="osbc_IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The net change during the reporting period in accrued interest receivable and other assets.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase (Decrease) in Accrued Interest Receivable and Other Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Change in accrued interest receivable and other assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GoodwillImpairmentLoss" xlink:label="us-gaap_GoodwillImpairmentLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillImpairmentLoss" xlink:to="us-gaap_GoodwillImpairmentLoss_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GoodwillImpairmentLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Goodwill, Impairment Loss</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GoodwillImpairmentLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impairment of goodwill</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans" xlink:label="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans" xlink:to="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of premium amortization/discount (accretions) of purchase account adjustments on loans.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Premium Amortization Discount (Accretion) of Purchase Accounting Adjustments on Loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Accretion of purchase accounting adjustment on time deposits</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings" xlink:label="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings" xlink:to="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of premium amortization/discount (accretions) of purchase account adjustments on notes payable and other borrowings.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Premium Amortization Discount Accretion Of Purchase Accounting Adjustments On Notes Payable and Other Borrowings</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of purchase accounting adjustment on notes payable and other borrowingsStock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AmortizationOfFinancingCosts" xlink:label="us-gaap_AmortizationOfFinancingCosts" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AmortizationOfFinancingCosts" xlink:to="us-gaap_AmortizationOfFinancingCosts_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AmortizationOfFinancingCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of Financing Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AmortizationOfFinancingCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of junior subordinated debentures issuance costs</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AmortizationOfSeniorNotesIssuanceCosts" xlink:label="osbc_AmortizationOfSeniorNotesIssuanceCosts" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AmortizationOfSeniorNotesIssuanceCosts" xlink:to="osbc_AmortizationOfSeniorNotesIssuanceCosts_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AmortizationOfSeniorNotesIssuanceCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of amortization expense attributable to senior notes issuance costs.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AmortizationOfSeniorNotesIssuanceCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization Of Senior Notes Issuance Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AmortizationOfSeniorNotesIssuanceCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of senior notes issuance costs</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities" xlink:label="osbc_IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities" xlink:to="osbc_IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The net change during the reporting period in accrued interest payable and other liabilities.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase (Decrease) in Accrued Interest Payable and Other Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Change in accrued interest payable and other liabilities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="us-gaap_ShareBasedCompensation" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensation" xlink:to="us-gaap_ShareBasedCompensation_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stock based compensation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ShareBasedCompensation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stock-based compensation</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Cash Provided by (Used in) Operating Activities, Continuing Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInOperatingActivities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net cash provided by operating activities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Cash Provided by (Used in) Investing Activities, Continuing Operations [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash flows from investing activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash Flows from Investing Activities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities" xlink:to="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from Maturities, Prepayments and Calls of Available-for-sale Securities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfAvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from maturities and calls including pay down of securities available-for-sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities" xlink:to="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from Sale of Available-for-sale Securities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from sales of securities available-for-sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Sales</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireAvailableForSaleSecurities" xlink:to="us-gaap_PaymentsToAcquireAvailableForSaleSecurities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments to Acquire Available-for-sale Securities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Purchases of securities available-for-sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PaymentsToAcquireAvailableForSaleSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Purchases</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities" xlink:to="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from Maturities, Prepayments and Calls of Held-to-maturity Securities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromMaturitiesPrepaymentsAndCallsOfHeldToMaturitySecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from maturities and calls including pay down of securities held-to-maturity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock" xlink:to="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments for (Proceeds from) Federal Home Loan Bank Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsForProceedsFromFederalHomeLoanBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net disbursements/proceeds from sales (purchases) of FHLBC stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForProceedsFromFederalReserveBankStock" xlink:label="us-gaap_PaymentsForProceedsFromFederalReserveBankStock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsForProceedsFromFederalReserveBankStock" xlink:to="us-gaap_PaymentsForProceedsFromFederalReserveBankStock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsForProceedsFromFederalReserveBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments for (Proceeds from) Federal Reserve Bank Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsForProceedsFromFederalReserveBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net disbursements/proceeds from (purchases) sales of FRB stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForProceedsFromLoansAndLeases" xlink:label="us-gaap_PaymentsForProceedsFromLoansAndLeases" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsForProceedsFromLoansAndLeases" xlink:to="us-gaap_PaymentsForProceedsFromLoansAndLeases_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsForProceedsFromLoansAndLeases_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments for (Proceeds from) Loans and Leases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsForProceedsFromLoansAndLeases_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net change in loans</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeathClaimOnBankOwnedLifeInsurance" xlink:label="osbc_DeathClaimOnBankOwnedLifeInsurance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeathClaimOnBankOwnedLifeInsurance" xlink:to="osbc_DeathClaimOnBankOwnedLifeInsurance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeathClaimOnBankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the death claim from bank owned life insurance during the reporting period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeathClaimOnBankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Death Claim on Bank Owned Life Insurance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="osbc_DeathClaimOnBankOwnedLifeInsurance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from claims on BOLI</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireProjects" xlink:label="us-gaap_PaymentsToAcquireProjects" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireProjects" xlink:to="us-gaap_PaymentsToAcquireProjects_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireProjects_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments to Acquire Projects</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsToAcquireProjects_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Improvements in other real estate owned</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromSaleOfOtherRealEstate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from Sale of Other Real Estate</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment" xlink:to="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromSaleOfPropertyPlantAndEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from disposition of premises and equipment</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:to="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments to Acquire Property, Plant, and Equipment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net purchases of premises and equipment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments to Acquire Businesses, Net of Cash Acquired</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsToAcquireBusinessesNetOfCashAcquired_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash paid for acquisition, net of cash and cash equivalent retained</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:to="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Cash Provided by (Used in) Investing Activities, Continuing Operations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_NetCashProvidedByUsedInInvestingActivities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net cash provided by (used in) investing activities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract" xlink:to="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Cash Provided by (Used in) Financing Activities, Continuing Operations [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash flows from financing activities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash Flows from Financing Activities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInDeposits" xlink:label="us-gaap_IncreaseDecreaseInDeposits" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInDeposits" xlink:to="us-gaap_IncreaseDecreaseInDeposits_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase (Decrease) in Deposits</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net change in deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase" xlink:label="us-gaap_ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase" xlink:to="us-gaap_ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from (Payments for) in Securities Sold under Agreements to Repurchase</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromPaymentsForInSecuritiesSoldUnderAgreementsToRepurchase_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net change in securities sold under repurchase agreements</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfShortTermDebt" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromRepaymentsOfShortTermDebt" xlink:to="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from (Repayments of) Short-term Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromRepaymentsOfShortTermDebt_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net change in other short-term borrowings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfDebtIssuanceCosts" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsOfDebtIssuanceCosts" xlink:to="us-gaap_PaymentsOfDebtIssuanceCosts_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments of Debt Issuance Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsOfDebtIssuanceCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payment of senior note issuance costs</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ProceedsFromIssuanceOfSeniorNotes" xlink:label="osbc_ProceedsFromIssuanceOfSeniorNotes" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ProceedsFromIssuanceOfSeniorNotes_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The cash inflow from notes, both current and noncurrent portions, borrowing with the highest claim on the assets of the entity in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle, if longer).Senior note holders are paid off in full before any payments are made to junior note holders.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ProceedsFromIssuanceOfSeniorNotes_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds From Issuance Of Senior Notes</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ProceedsFromIssuanceOfSeniorNotes_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from the issuance of senior notes</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RepaymentsOfSubordinatedDebt" xlink:label="us-gaap_RepaymentsOfSubordinatedDebt" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RepaymentsOfSubordinatedDebt" xlink:to="us-gaap_RepaymentsOfSubordinatedDebt_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RepaymentsOfSubordinatedDebt_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Repayments of Subordinated Debt</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_RepaymentsOfSubordinatedDebt_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Repayment of subordinate debt</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromRepaymentsOfNotesPayable" xlink:label="us-gaap_ProceedsFromRepaymentsOfNotesPayable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromRepaymentsOfNotesPayable" xlink:to="us-gaap_ProceedsFromRepaymentsOfNotesPayable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromRepaymentsOfNotesPayable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from (Repayments of) Notes Payable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromRepaymentsOfNotesPayable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net change in notes payable and other borrowings</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProceedsFromRepaymentsOfNotesPayable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Repayments of notes payable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromStockOptionsExercised" xlink:label="us-gaap_ProceedsFromStockOptionsExercised" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from Stock Options Exercised</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from exercise of stock options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ProceedsFromStockOptionsExercised_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash received from options exercised</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsOfDividendsCommonStock" xlink:label="us-gaap_PaymentsOfDividendsCommonStock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsOfDividendsCommonStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments of Ordinary Dividends, Common Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsOfDividendsCommonStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividends paid common stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsForRepurchaseOfCommonStock" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Purchase of treasury stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:label="us-gaap_PaymentsForRepurchaseOfCommonStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Purchases of treasury stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:label="us-gaap_NetCashProvidedByUsedInFinancingActivities" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_CashAndCashEquivalentsPeriodIncreaseDecrease_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net change in cash and cash equivalents</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Supplemental Cash Flow Information [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SupplementalCashFlowInformationAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Supplemental cash flow information</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxesPaidNet" xlink:label="us-gaap_IncomeTaxesPaidNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxesPaidNet" xlink:to="us-gaap_IncomeTaxesPaidNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Taxes Paid, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxesPaidNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income taxes paid</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_InterestPaidForDeposits" xlink:label="osbc_InterestPaidForDeposits" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_InterestPaidForDeposits" xlink:to="osbc_InterestPaidForDeposits_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_InterestPaidForDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The amount of cash paid during the current period for interest on deposits.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_InterestPaidForDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Paid for Deposits</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_InterestPaidForDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest paid for deposits</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_InterestPaidForBorrowings" xlink:label="osbc_InterestPaidForBorrowings" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_InterestPaidForBorrowings" xlink:to="osbc_InterestPaidForBorrowings_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_InterestPaidForBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The amount of cash paid for interest on borrowings during the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_InterestPaidForBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Paid for Borrowings</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_InterestPaidForBorrowings_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest paid for borrowings</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_NonCashTransferOfLoansToOtherRealEstateOwned" xlink:label="osbc_NonCashTransferOfLoansToOtherRealEstateOwned" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_NonCashTransferOfLoansToOtherRealEstateOwned" xlink:to="osbc_NonCashTransferOfLoansToOtherRealEstateOwned_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_NonCashTransferOfLoansToOtherRealEstateOwned_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This element represents the non cash transfer of loans to other real estate owned during the reporting period. Part non cash refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_NonCashTransferOfLoansToOtherRealEstateOwned_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Non Cash Transfer of Loans to Other Real Estate Owned</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_NonCashTransferOfLoansToOtherRealEstateOwned_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Non-cash transfer of loans to other real estate owned</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_NonCashTransferOfPremisesToOtherRealEstateOwned" xlink:label="osbc_NonCashTransferOfPremisesToOtherRealEstateOwned" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_NonCashTransferOfPremisesToOtherRealEstateOwned" xlink:to="osbc_NonCashTransferOfPremisesToOtherRealEstateOwned_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_NonCashTransferOfPremisesToOtherRealEstateOwned_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">This element represents the non cash transfer of premises to other real estate owned during the reporting period. Part non cash refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_NonCashTransferOfPremisesToOtherRealEstateOwned_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Non Cash Transfer of Premises to Other Real Estate Owned</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_NonCashTransferOfPremisesToOtherRealEstateOwned_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Non-cash transfer of premises to other real estate owned</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity" xlink:label="osbc_TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity" xlink:to="osbc_TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Value of investments transferred between the entity's available-for-sale investments and held-to-maturity investments in noncash transactions.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Transfers Between Investments Available-for-Sale and Investments Held-To-Maturity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Non-cash transfer of securities available-for-sale to securities held-to-maturity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementOfStockholdersEquityAbstract" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementOfStockholdersEquityAbstract" xlink:to="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementOfStockholdersEquityAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Consolidated Statements of Changes in Stockholders' Equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementEquityComponentsAxis" xlink:label="us-gaap_StatementEquityComponentsAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementEquityComponentsAxis" xlink:to="us-gaap_StatementEquityComponentsAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementEquityComponentsAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Components [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EquityComponentDomain" xlink:label="us-gaap_EquityComponentDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EquityComponentDomain" xlink:to="us-gaap_EquityComponentDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EquityComponentDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Component [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EquityComponentDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Component [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommonStockMember" xlink:label="us-gaap_CommonStockMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommonStockMember" xlink:to="us-gaap_CommonStockMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommonStockMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Common Stock [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommonStockMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Common Stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdditionalPaidInCapitalMember" xlink:label="us-gaap_AdditionalPaidInCapitalMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdditionalPaidInCapitalMember" xlink:to="us-gaap_AdditionalPaidInCapitalMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Additional Paid In Capital [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AdditionalPaidInCapitalMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Additional Paid In Capital</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetainedEarningsMember" xlink:label="us-gaap_RetainedEarningsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetainedEarningsMember" xlink:to="us-gaap_RetainedEarningsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RetainedEarningsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Retained Earnings [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RetainedEarningsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Retained Earnings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedOtherComprehensiveIncomeMember" xlink:to="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Accumulated Other Comprehensive Income [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AccumulatedOtherComprehensiveIncomeMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Accumulated Other Comprehensive Income (Loss)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:label="us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInStockholdersEquityRollForward" xlink:to="us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase (Decrease) in Stockholders' Equity [Roll Forward]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase (Decrease) in Stockholders' Equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DividendsCommonStock" xlink:label="us-gaap_DividendsCommonStock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DividendsCommonStock" xlink:to="us-gaap_DividendsCommonStock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DividendsCommonStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividends, Common Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_DividendsCommonStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividends declared and paid</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ChangeInRestrictedStock" xlink:label="osbc_ChangeInRestrictedStock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ChangeInRestrictedStock" xlink:to="osbc_ChangeInRestrictedStock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ChangeInRestrictedStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of change in restricted stock during the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ChangeInRestrictedStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Change In Restricted Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_ChangeInRestrictedStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Vesting of restricted stock</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect" xlink:label="osbc_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect" xlink:to="osbc_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of increase (decrease) in accumulated other comprehensive income (AOCI) for reclassification to retained earnings of tax effect from remeasurement of deferred tax pursuant to Tax Cuts and Jobs Act of 2017.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Cuts and Jobs Act of 2017, Reclassification from AOCI to Retained Earnings, Tax Effect</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Reclassification of stranded tax effects</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RecaptureOfRestrictedStock" xlink:label="osbc_RecaptureOfRestrictedStock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_RecaptureOfRestrictedStock" xlink:to="osbc_RecaptureOfRestrictedStock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_RecaptureOfRestrictedStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the value of restricted stock recapture adjustment during the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RecaptureOfRestrictedStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Recapture of Restricted Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_RecaptureOfRestrictedStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Recapture of restricted stock</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConsolidationPolicyTextBlock" xlink:to="us-gaap_ConsolidationPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConsolidationPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Principles of Consolidation</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SegmentReportingPolicyPolicyTextBlock" xlink:label="us-gaap_SegmentReportingPolicyPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SegmentReportingPolicyPolicyTextBlock" xlink:to="us-gaap_SegmentReportingPolicyPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SegmentReportingPolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Segment Reporting</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CashAndCashEquivalentsPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash and Cash Equivalents</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MarketableSecuritiesPolicy" xlink:label="us-gaap_MarketableSecuritiesPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MarketableSecuritiesPolicy" xlink:to="us-gaap_MarketableSecuritiesPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MarketableSecuritiesPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Marketable Securities, Available-for-sale Securities, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MarketableSecuritiesPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock" xlink:label="osbc_FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock" xlink:to="osbc_FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Disclosure of valuation methods for stocks held in the Federal Reserve Bank of Chicago and Federal Home Loan Bank of Chicago.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank and Federal Reserve Bank Stock [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank and Federal Reserve Bank Stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinanceLoanAndLeaseReceivablesHeldForSalePolicy" xlink:label="us-gaap_FinanceLoanAndLeaseReceivablesHeldForSalePolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLoanAndLeaseReceivablesHeldForSalePolicy" xlink:to="us-gaap_FinanceLoanAndLeaseReceivablesHeldForSalePolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinanceLoanAndLeaseReceivablesHeldForSalePolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Finance, Loan and Lease Receivables, Held-for-sale, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinanceLoanAndLeaseReceivablesHeldForSalePolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans Held-for-Sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinanceLoanAndLeaseReceivablesHeldForInvestmentPolicy" xlink:label="us-gaap_FinanceLoanAndLeaseReceivablesHeldForInvestmentPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLoanAndLeaseReceivablesHeldForInvestmentPolicy" xlink:to="us-gaap_FinanceLoanAndLeaseReceivablesHeldForInvestmentPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinanceLoanAndLeaseReceivablesHeldForInvestmentPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Finance, Loan and Lease Receivables, Held-for-investment, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinanceLoanAndLeaseReceivablesHeldForInvestmentPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskCreditRisk" xlink:label="us-gaap_ConcentrationRiskCreditRisk" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskCreditRisk" xlink:to="us-gaap_ConcentrationRiskCreditRisk_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskCreditRisk_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration Risk, Credit Risk, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConcentrationRiskCreditRisk_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration of Credit Risk</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinanceLoansAndLeasesReceivablePolicy" xlink:label="us-gaap_FinanceLoansAndLeasesReceivablePolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLoansAndLeasesReceivablePolicy" xlink:to="us-gaap_FinanceLoansAndLeasesReceivablePolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinanceLoansAndLeasesReceivablePolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Finance, Loans and Leases Receivable, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinanceLoansAndLeasesReceivablePolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Lease financing receivables</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableNonaccrualLoanAndLeaseStatusPolicy" xlink:label="us-gaap_LoansAndLeasesReceivableNonaccrualLoanAndLeaseStatusPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivableNonaccrualLoanAndLeaseStatusPolicy" xlink:to="us-gaap_LoansAndLeasesReceivableNonaccrualLoanAndLeaseStatusPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivableNonaccrualLoanAndLeaseStatusPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Nonaccrual Loan and Lease Status, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableNonaccrualLoanAndLeaseStatusPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Nonaccrual loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableTroubledDebtRestructuringPolicy" xlink:label="us-gaap_LoansAndLeasesReceivableTroubledDebtRestructuringPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivableTroubledDebtRestructuringPolicy" xlink:to="us-gaap_LoansAndLeasesReceivableTroubledDebtRestructuringPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivableTroubledDebtRestructuringPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Troubled Debt Restructuring Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableTroubledDebtRestructuringPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Troubled Debt Restructurings (TDRs)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivablePolicyPolicyTextBlock" xlink:label="us-gaap_ImpairedFinancingReceivablePolicyPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivablePolicyPolicyTextBlock" xlink:to="us-gaap_ImpairedFinancingReceivablePolicyPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivablePolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivablePolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivablePastDueStatusPolicy" xlink:label="us-gaap_LoansAndLeasesReceivablePastDueStatusPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivablePastDueStatusPolicy" xlink:to="us-gaap_LoansAndLeasesReceivablePastDueStatusPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivablePastDueStatusPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Past Due Status, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansAndLeasesReceivablePastDueStatusPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">90-Days or Greater Past Due Loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy" xlink:label="us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy" xlink:to="us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Allowance for Loan Losses Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableAllowanceForLoanLossesPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Allowance for Loan Losses</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:to="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property, Plant and Equipment, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Premises and Equipment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateOwnedValuationAllowancePolicy" xlink:label="us-gaap_RealEstateOwnedValuationAllowancePolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateOwnedValuationAllowancePolicy" xlink:to="us-gaap_RealEstateOwnedValuationAllowancePolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateOwnedValuationAllowancePolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Owned, Valuation Allowance, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RealEstateOwnedValuationAllowancePolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Real Estate Owned ("OREO")</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy" xlink:label="us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy" xlink:to="us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Transfers and Servicing of Financial Assets, Servicing of Financial Assets, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TransfersAndServicingOfFinancialAssetsServicingOfFinancialAssetsPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Servicing Rights</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_LifeInsuranceBankOwnedPolicyTextBlock" xlink:label="osbc_LifeInsuranceBankOwnedPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_LifeInsuranceBankOwnedPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Disclosure of accounting policy for (BOLI) bank owned life insurance including the amount of cash surrender value that could be received as of the date of the statement of financial position, any restrictions on the company's ability to obtain the value of the life insurance policy on surrender, or any other additional information desired to be disclosed.</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy" xlink:label="us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy" xlink:to="us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Goodwill and Intangible Assets, Intangible Assets, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_GoodwillAndIntangibleAssetsIntangibleAssetsPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Goodwill and Core Deposit Intangible Assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommitmentsAndContingenciesPolicyTextBlock" xlink:label="us-gaap_CommitmentsAndContingenciesPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommitmentsAndContingenciesPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commitments and Contingencies, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommitmentsAndContingenciesPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loss Contingencies</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_WealthManagementPolicyTextBlock" xlink:label="osbc_WealthManagementPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_WealthManagementPolicyTextBlock" xlink:to="osbc_WealthManagementPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_WealthManagementPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Disclosure of accounting policy for wealth management.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_WealthManagementPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Wealth Management [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_WealthManagementPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Wealth Management</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost" xlink:label="us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost" xlink:to="us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Advertising Cost, Policy, Expensed Advertising Cost [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AdvertisingCostPolicyExpensedAdvertisingCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Advertising Costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy" xlink:to="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation, Option and Incentive Plans Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationOptionAndIncentivePlansPolicy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Incentive Plan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxPolicyTextBlock" xlink:label="us-gaap_IncomeTaxPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxPolicyTextBlock" xlink:to="us-gaap_IncomeTaxPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Tax, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Taxes</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerSharePolicyTextBlock" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerSharePolicyTextBlock" xlink:to="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Earnings Per Share, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EarningsPerSharePolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Earnings Per Common Share ("EPS")</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TreasuryStockPolicyTextBlock" xlink:label="osbc_TreasuryStockPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TreasuryStockPolicyTextBlock" xlink:to="osbc_TreasuryStockPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TreasuryStockPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Disclosure of accounting policy for treasury stock of the entity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TreasuryStockPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Treasury Stock [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TreasuryStockPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Treasury Stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativesPolicyTextBlock" xlink:label="us-gaap_DerivativesPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativesPolicyTextBlock" xlink:to="us-gaap_DerivativesPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativesPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivatives, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativesPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivative Financial Instruments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComprehensiveIncomePolicyPolicyTextBlock" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock" xlink:to="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Comprehensive Income, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ComprehensiveIncomePolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Comprehensive Income (Loss)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:to="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">New Accounting Pronouncements, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NewAccountingPronouncementsPolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Recent Accounting Pronouncements</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventsPolicyPolicyTextBlock" xlink:label="us-gaap_SubsequentEventsPolicyPolicyTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsequentEventsPolicyPolicyTextBlock" xlink:to="us-gaap_SubsequentEventsPolicyPolicyTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SubsequentEventsPolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subsequent Events, Policy [Policy Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SubsequentEventsPolicyPolicyTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subsequent Events</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:label="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock" xlink:to="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Recognized Identified Assets Acquired and Liabilities Assumed [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfRecognizedIdentifiedAssetsAcquiredAndLiabilitiesAssumedTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Summary of acquisition</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTableTextBlock" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTableTextBlock" xlink:to="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTableTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities Acquired During Period [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Acquired Loans as of Acquisition Date</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock" xlink:label="osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock" xlink:to="osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of the reconciliation of available-for-sale securities and held-to-maturity securities from cost basis to fair value.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Available for Sale Securities and Held to Maturity Securities Reconciliation [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of amortized cost and fair value of the securities portfolio and corresponding amounts of gross unrealized gains and losses recognized in accumulated other comprehensive loss</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock" xlink:to="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investments Classified by Contractual Maturity Date [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of fair value, amortized cost and weighted average yield of debt securities by contractual maturity along with securities not due at a single maturity date, primarily mortgage-backed securities (MBS), asset-backed securities, and collateralized loan obligations</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ScheduleOfAmortizedCostAndFairValueOfSecuritiesThatExceedTenPercentOfStockholdersEquityTableTextBlock" xlink:label="osbc_ScheduleOfAmortizedCostAndFairValueOfSecuritiesThatExceedTenPercentOfStockholdersEquityTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ScheduleOfAmortizedCostAndFairValueOfSecuritiesThatExceedTenPercentOfStockholdersEquityTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of amortized cost and fair value of securities that exceed 10% of stockholders equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock" xlink:label="us-gaap_ScheduleOfUnrealizedLossOnInvestmentsTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PastDueFinancingReceivablesTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of aged analysis of past due loans by class of loans</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable Credit Quality Indicators [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableCreditQualityIndicatorsTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of credit quality indicators by class of loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivablesTableTextBlock" xlink:label="us-gaap_ImpairedFinancingReceivablesTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivablesTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of impaired loans by class of loan</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ScheduleOfTroubledDebtRestructuringsOnFinancingReceivablesByTypeOfModificationTableTextBlock" xlink:label="osbc_ScheduleOfTroubledDebtRestructuringsOnFinancingReceivablesByTypeOfModificationTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ScheduleOfTroubledDebtRestructuringsOnFinancingReceivablesByTypeOfModificationTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of financing receivables classified as troubled debt restructurings by type of modification.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ScheduleOfTroubledDebtRestructuringsOnFinancingReceivablesByTypeOfModificationTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Troubled Debt Restructurings on Financing Receivables by Type of Modification [Table Text Block]</label>
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    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableDiscountTableTextBlock" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableDiscountTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableDiscountTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of accretable discount relating to certain loans acquired in a transfer.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableDiscountTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Discount [Table Text Block]</label>
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    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ScheduleOfFinancingReceivablesToRelatedPartiesTableTextBlock" xlink:label="osbc_ScheduleOfFinancingReceivablesToRelatedPartiesTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ScheduleOfFinancingReceivablesToRelatedPartiesTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of the activity of loans to principal officers, directors, and their affiliates, which are made in the ordinary course of business.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ScheduleOfFinancingReceivablesToRelatedPartiesTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Financing Receivables to Related Parties [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ScheduleOfFinancingReceivablesToRelatedPartiesTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of loans to principal officers, directors, and their affiliates, made in the ordinary course of business</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock" xlink:label="us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Allowance for Credit Losses on Financing Receivables [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AllowanceForCreditLossesOnFinancingReceivablesTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of changes in the allowance for loan losses by segment of loans based on method of impairment</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RealEstateAcquiredThroughForeclosureRollForwardTableTextBlock" xlink:label="osbc_RealEstateAcquiredThroughForeclosureRollForwardTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_RealEstateAcquiredThroughForeclosureRollForwardTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of the change in other real estate on properties acquired through foreclosure.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RealEstateAcquiredThroughForeclosureRollForwardTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Acquired Through Foreclosure, Roll Forward [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_RealEstateAcquiredThroughForeclosureRollForwardTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of activity in the other real estate owned (OREO) portfolio, net of valuation reserve</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OtherRealEstateValuationAllowanceRollForwardTableTextBlock" xlink:label="osbc_OtherRealEstateValuationAllowanceRollForwardTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OtherRealEstateValuationAllowanceRollForwardTableTextBlock" xlink:to="osbc_OtherRealEstateValuationAllowanceRollForwardTableTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OtherRealEstateValuationAllowanceRollForwardTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of the change in valuation allowance of other real estate on properties acquired through foreclosure.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OtherRealEstateValuationAllowanceRollForwardTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Real Estate Valuation Allowance [Roll Forward] [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OtherRealEstateValuationAllowanceRollForwardTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of activity in valuation allowance</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OtherRealEstateExpensesRelatedToForeclosedAssetsTableTextBlock" xlink:label="osbc_OtherRealEstateExpensesRelatedToForeclosedAssetsTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OtherRealEstateExpensesRelatedToForeclosedAssetsTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of expenses related to foreclosed assets, net of lease revenue. Foreclosed assets include all assets obtained in full or partial satisfaction of a debt arrangement through foreclosure proceedings.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OtherRealEstateExpensesRelatedToForeclosedAssetsTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Real Estate Expenses Related to Foreclosed Assets [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OtherRealEstateExpensesRelatedToForeclosedAssetsTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of expenses related to foreclosed assets, net of lease revenue</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property, Plant and Equipment [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of components of premises and equipment</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ScheduleOfDepositsTableTextBlock" xlink:label="osbc_ScheduleOfDepositsTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ScheduleOfDepositsTableTextBlock" xlink:to="osbc_ScheduleOfDepositsTableTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ScheduleOfDepositsTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of different types of deposits liabilities held by the entity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ScheduleOfDepositsTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Deposits [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ScheduleOfDepositsTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of major classifications of deposits</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock" xlink:label="osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock" xlink:to="osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tabular disclosure of the aggregate amount of maturities for time deposits for each of the five years following the date of the latest fiscal year presented.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Maturities of Time Deposit [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Summary of scheduled maturities of time deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfDebtInstrumentsTextBlock" xlink:label="us-gaap_ScheduleOfDebtInstrumentsTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfDebtInstrumentsTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Long-term Debt Instruments [Table Text Block]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfDebtInstrumentsTextBlock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Summary of borrowings and junior subordinated debentures</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xlink:label="us-gaap_ScheduleOfMaturitiesOfLongTermDebtTableTextBlock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseNextTwelveMonths" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearTwo" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearThree" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFour_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Finite-Lived Intangible Assets, Amortization Expense, Year Four</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xlink:label="us-gaap_FiniteLivedIntangibleAssetsAmortizationExpenseYearFive" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:to="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentByTypeAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property, Plant and Equipment, Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:to="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property Plant And Equipment Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property, Plant and Equipment, Type [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BuildingMember" xlink:label="us-gaap_BuildingMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BuildingMember" xlink:to="us-gaap_BuildingMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BuildingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Building [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BuildingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Buildings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BuildingImprovementsMember" xlink:label="us-gaap_BuildingImprovementsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BuildingImprovementsMember" xlink:to="us-gaap_BuildingImprovementsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BuildingImprovementsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Building Improvements [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BuildingImprovementsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Building improvements</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FurnitureAndFixturesMember" xlink:label="us-gaap_FurnitureAndFixturesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FurnitureAndFixturesMember" xlink:to="us-gaap_FurnitureAndFixturesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Furniture And Fixtures [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FurnitureAndFixturesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Furniture and equipment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeAxis" xlink:label="srt_RangeAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeAxis" xlink:to="srt_RangeAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_RangeAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Range [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RangeMember" xlink:label="srt_RangeMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RangeMember" xlink:to="srt_RangeMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_RangeMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Range [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_RangeMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Range [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MinimumMember" xlink:label="srt_MinimumMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MinimumMember" xlink:to="srt_MinimumMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_MinimumMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_MinimumMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MaximumMember" xlink:label="srt_MaximumMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MaximumMember" xlink:to="srt_MaximumMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_MaximumMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Maximum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_MaximumMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Maximum</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentLineItems" xlink:to="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property, Plant and Equipment [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Premises and equipment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentUsefulLife" xlink:to="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property, Plant and Equipment, Useful Life</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentUsefulLife_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Useful lives</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialAssetsAbstract" xlink:label="us-gaap_TransfersAndServicingOfFinancialAssetsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TransfersAndServicingOfFinancialAssetsAbstract" xlink:to="us-gaap_TransfersAndServicingOfFinancialAssetsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TransfersAndServicingOfFinancialAssetsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Transfers and Servicing of Financial Assets [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TransfersAndServicingOfFinancialAssetsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Transfers and Servicing of Financial Assets</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_MortgageLoansServicingAssetAtFairValueAmount" xlink:label="osbc_MortgageLoansServicingAssetAtFairValueAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_MortgageLoansServicingAssetAtFairValueAmount" xlink:to="osbc_MortgageLoansServicingAssetAtFairValueAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_MortgageLoansServicingAssetAtFairValueAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair value as of the balance sheet date of mortgage loans representing net future revenues from contractually specified servicing fees, late charges, and other ancillary revenues, in excess of future costs related to servicing arrangements.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_MortgageLoansServicingAssetAtFairValueAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Loans Servicing Asset at Fair Value Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_MortgageLoansServicingAssetAtFairValueAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage loans serviced for others</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_NumberOfBranchesOperated" xlink:label="osbc_NumberOfBranchesOperated" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_NumberOfBranchesOperated" xlink:to="osbc_NumberOfBranchesOperated_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_NumberOfBranchesOperated_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of bank branches operated.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_NumberOfBranchesOperated_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of Branches Operated</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_NumberOfBranchesOperated_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of bank branches operated</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet" xlink:to="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Acquisition price</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PaymentsToAcquireBusinessesGross" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PaymentsToAcquireBusinessesGross" xlink:to="us-gaap_PaymentsToAcquireBusinessesGross_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Payments to Acquire Businesses, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net cash paid</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_PaymentsToAcquireBusinessesGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash consideration paid</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubordinatedDebt" xlink:label="us-gaap_SubordinatedDebt" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubordinatedDebt" xlink:to="us-gaap_SubordinatedDebt_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SubordinatedDebt_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subordinated Debt.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SubordinatedDebt_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subordinated debentures retired</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Goodwill" xlink:label="us-gaap_Goodwill" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Goodwill" xlink:to="us-gaap_Goodwill_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Goodwill_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Goodwill</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Core deposit intangible</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment" xlink:label="us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Business Combination, Provisional Information, Initial Accounting Incomplete, Adjustment, Property, Plant, and Equipment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentPropertyPlantAndEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Valuation adjustment, fixed assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentFinancialAssets" xlink:label="us-gaap_BusinessCombinationProvisionalInformationInitialAccountingIncompleteAdjustmentFinancialAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancialAssetAcquiredAndNoCreditDeteriorationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Non-PCI</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAtFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, at Acquisition, at Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveTerseLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAtFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance: Acquired and accounted for ASC 310-30</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAtFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodAtAcquisitionAtFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">PCI loans, net of purchase accounting adjustments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodContractuallyRequiredPaymentsReceivableAtAcquisition" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodContractuallyRequiredPaymentsReceivableAtAcquisition" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodContractuallyRequiredPaymentsReceivableAtAcquisition_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Contractually Required Payments Receivable at Acquisition</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodContractuallyRequiredPaymentsReceivableAtAcquisition_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Contractually required principal and interest payments</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsNotExpectedToBeCollectedAtAcquisition" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsNotExpectedToBeCollectedAtAcquisition" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsNotExpectedToBeCollectedAtAcquisition_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of cash flows not expected to be collected at acquisition of acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsNotExpectedToBeCollectedAtAcquisition_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Cash Flows Not Expected to be Collected at Acquisition</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsNotExpectedToBeCollectedAtAcquisition_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Best estimate of contractual cash flows not expected to be collected</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsExpectedToBeCollectedAtAcquisition" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsExpectedToBeCollectedAtAcquisition" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsExpectedToBeCollectedAtAcquisition" xlink:to="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsExpectedToBeCollectedAtAcquisition_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsExpectedToBeCollectedAtAcquisition_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Acquired During Period, Cash Flows Expected to be Collected at Acquisition</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsExpectedToBeCollectedAtAcquisition_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Best estimate of contractual cash flows expected to be collected</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfCompensatingBalancesTable" xlink:label="us-gaap_ScheduleOfCompensatingBalancesTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfCompensatingBalancesTable" xlink:to="us-gaap_ScheduleOfCompensatingBalancesTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashAndCashEquivalentsAxis" xlink:label="us-gaap_CashAndCashEquivalentsAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashAndCashEquivalentsAxis" xlink:to="us-gaap_CashAndCashEquivalentsAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CashAndCashEquivalentsAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash and Cash Equivalents [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember" xlink:to="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Restricted Cash And Cash Equivalents Cash And Cash Equivalents [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RestrictedCashAndCashEquivalentsCashAndCashEquivalentsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash and Cash Equivalents [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalReserveBankRegulatoryReserveMember" xlink:label="osbc_FederalReserveBankRegulatoryReserveMember" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalReserveBankRegulatoryReserveMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents activity related to Federal Reserve Bank regulatory reserves and clearing requirements.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalReserveBankRegulatoryReserveMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Reserve Bank Regulatory Reserve [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalReserveBankRegulatoryReserveMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Reserve Bank average regulatory reserve</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CompensatingBalancesLineItems" xlink:label="us-gaap_CompensatingBalancesLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CompensatingBalancesLineItems" xlink:to="us-gaap_CompensatingBalancesLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CompensatingBalancesLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Compensating Balances [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CompensatingBalancesLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other disclosures</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CompensatingBalanceAmount" xlink:label="us-gaap_CompensatingBalanceAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CompensatingBalanceAmount" xlink:to="us-gaap_CompensatingBalanceAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CompensatingBalanceAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Compensating Balance, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CompensatingBalanceAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Balances</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AverageReserveBalanceWithReserveBank" xlink:label="osbc_AverageReserveBalanceWithReserveBank" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AverageReserveBalanceWithReserveBank" xlink:to="osbc_AverageReserveBalanceWithReserveBank_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AverageReserveBalanceWithReserveBank_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The amount of average compensating balance arrangement that is maintained with the Reserve Bank, under an agreement for a bank loan or future credit availability.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AverageReserveBalanceWithReserveBank_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Average Reserve Balance With Reserve Bank</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AverageReserveBalanceWithReserveBank_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Balances</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InvestmentHoldingsTable" xlink:label="us-gaap_InvestmentHoldingsTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentHoldingsTable" xlink:to="us-gaap_InvestmentHoldingsTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentHoldingsTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investment Holdings [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InvestmentHoldingsLineItems" xlink:label="us-gaap_InvestmentHoldingsLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentHoldingsLineItems" xlink:to="us-gaap_InvestmentHoldingsLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentHoldingsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investment Holdings [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InvestmentHoldingsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale securities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Gross Realized Losses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gross realized losses on securities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pretax realized losses on sale of available-for-sale securities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStockAbstract" xlink:label="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStockAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStockAbstract" xlink:to="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStockAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStockAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Stock and Federal Reserve Bank Stock [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FederalHomeLoanBankStockAndFederalReserveBankStockAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FHLB and FRB Stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankStock" xlink:label="us-gaap_FederalHomeLoanBankStock" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FederalHomeLoanBankStock" xlink:to="us-gaap_FederalHomeLoanBankStock_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FederalHomeLoanBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FederalHomeLoanBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FHLBC stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_FederalHomeLoanBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Bank owned FHLBC stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalReserveBankStock" xlink:label="us-gaap_FederalReserveBankStock" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FederalReserveBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Reserve Bank Stock</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FederalReserveBankStock_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FRB stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByBenchmarkAxis" xlink:to="us-gaap_ConcentrationRiskByBenchmarkAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskByBenchmarkAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration Risk Benchmark [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskBenchmarkDomain" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskBenchmarkDomain" xlink:to="us-gaap_ConcentrationRiskBenchmarkDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration Risk Benchmark [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConcentrationRiskBenchmarkDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration Risk Benchmark [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockholdersEquityTotalMember" xlink:label="us-gaap_StockholdersEquityTotalMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StockholdersEquityTotalMember" xlink:to="us-gaap_StockholdersEquityTotalMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockholdersEquityTotalMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stockholders Equity Total [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockholdersEquityTotalMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stockholders' Equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentContractCounterpartyAxis" xlink:label="invest_InvestmentContractCounterpartyAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="invest_InvestmentContractCounterpartyAxis" xlink:to="invest_InvestmentContractCounterpartyAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="invest_InvestmentContractCounterpartyAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investment Contract Counterparty [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_InvestmentContractCounterpartyDomain" xlink:label="invest_InvestmentContractCounterpartyDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="invest_InvestmentContractCounterpartyDomain" xlink:to="invest_InvestmentContractCounterpartyDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="invest_InvestmentContractCounterpartyDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investment Contract Counterparty [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="invest_InvestmentContractCounterpartyDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investment Contract Counterparty [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_GCOEducationLoanFundingCorpMember" xlink:label="osbc_GCOEducationLoanFundingCorpMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_GCOEducationLoanFundingCorpMember" xlink:to="osbc_GCOEducationLoanFundingCorpMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_GCOEducationLoanFundingCorpMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the concept about the concentration percentage derived for GCO Education Loan Funding Corp, an issuer greater than 10% of stockholders equity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_GCOEducationLoanFundingCorpMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">G C O Education Loan Funding Corp [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_GCOEducationLoanFundingCorpMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">GCO Education Loan Funding Corp</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TowdPointMortgageTrustMember" xlink:label="osbc_TowdPointMortgageTrustMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TowdPointMortgageTrustMember" xlink:to="osbc_TowdPointMortgageTrustMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TowdPointMortgageTrustMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the concept about the concentration percentage derived for Towd Point Mortgage Trust, an issuer greater than 10% of stockholders equity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TowdPointMortgageTrustMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Towd Point Mortgage Trust [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TowdPointMortgageTrustMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Towd Point Mortgage Trust</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_StudentMarketingAssociationMember" xlink:label="osbc_StudentMarketingAssociationMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_StudentMarketingAssociationMember" xlink:to="osbc_StudentMarketingAssociationMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_StudentMarketingAssociationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the information related to Student Loan Marketing Assocation, an issuer greater than 10% of stockholders equity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_StudentMarketingAssociationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Student Marketing Association [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_StudentMarketingAssociationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Student Marketing Association [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentAxis" xlink:label="us-gaap_FinancialInstrumentAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancialInstrumentAxis" xlink:to="us-gaap_FinancialInstrumentAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancialInstrumentAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial Instrument [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain" xlink:to="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Transfers And Servicing Of Financial Instruments Types Of Financial Instruments [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TransfersAndServicingOfFinancialInstrumentsTypesOfFinancialInstrumentsDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial Instruments [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USTreasurySecuritiesMember" xlink:label="us-gaap_USTreasurySecuritiesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_USTreasurySecuritiesMember" xlink:to="us-gaap_USTreasurySecuritiesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_USTreasurySecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">U S Treasury Securities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_USTreasurySecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">U.S. Treasury</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember" xlink:label="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember" xlink:to="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">U S Government Corporations And Agencies Securities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_USGovernmentCorporationsAndAgenciesSecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">U.S. government agencies</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:to="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">U S States And Political Subdivisions [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_USStatesAndPoliticalSubdivisionsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">States and political subdivisions</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CorporateBondSecuritiesMember" xlink:label="us-gaap_CorporateBondSecuritiesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CorporateBondSecuritiesMember" xlink:to="us-gaap_CorporateBondSecuritiesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CorporateBondSecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Corporate Bond Securities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CorporateBondSecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Corporate bonds</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralizedMortgageObligationsMember" xlink:label="us-gaap_CollateralizedMortgageObligationsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CollateralizedMortgageObligationsMember" xlink:to="us-gaap_CollateralizedMortgageObligationsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CollateralizedMortgageObligationsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Collateralized Mortgage Obligations [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CollateralizedMortgageObligationsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Collateralized mortgage obligations</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetBackedSecuritiesMember" xlink:label="us-gaap_AssetBackedSecuritiesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetBackedSecuritiesMember" xlink:to="us-gaap_AssetBackedSecuritiesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AssetBackedSecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Asset Backed Securities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AssetBackedSecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Asset-backed securities</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalFamilyEducationLoanProgramMember" xlink:label="osbc_FederalFamilyEducationLoanProgramMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalFamilyEducationLoanProgramMember" xlink:to="osbc_FederalFamilyEducationLoanProgramMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalFamilyEducationLoanProgramMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents asset backed securities backed by student loans originated under the Federal Family Education Loan program.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalFamilyEducationLoanProgramMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Family Education Loan Program [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalFamilyEducationLoanProgramMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FFEL</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember" xlink:label="osbc_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember" xlink:to="osbc_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt securities collateralized by real estate mortgage loans (mortgages), issued by US government agencies, for example, but not limited to, Government National Mortgage Association (GNMA or Ginnie Mae). Excludes US treasury securities and debt issued by government-sponsored Enterprises (GSEs), for example, but is not limited to, Federal Home Loan Mortgage Corporation (FHLMC or Freddie Mac), Federal National Mortgage Association (FNMA or Fannie Mae), and the Federal Home Loan Bank (FHLB).</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Backed Securities Issued By U S Government Agencies [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">U.S. government agency mortgage-backed</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAbstract" xlink:label="us-gaap_AvailableForSaleSecuritiesAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesAbstract" xlink:to="us-gaap_AvailableForSaleSecuritiesAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Available-for-Sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesAmortizedCost" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecuritiesAmortizedCost_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Amortized Cost Basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortized Cost</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gross Unrealized Gains</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xlink:label="us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available for Sale Securities Gross Unrealized Loss Accumulated in Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesAccumulatedGrossUnrealizedLossBeforeTax_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gross Unrealized Losses</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MarketableSecuritiesAbstract" xlink:label="us-gaap_MarketableSecuritiesAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MarketableSecuritiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Marketable Securities, Equity Securities [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MarketableSecuritiesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other disclosures</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_PercentageOfOutstandingPrincipalAmountOfLoansGuaranteedByUsDepartmentOfEducation" xlink:label="osbc_PercentageOfOutstandingPrincipalAmountOfLoansGuaranteedByUsDepartmentOfEducation" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_PercentageOfOutstandingPrincipalAmountOfLoansGuaranteedByUsDepartmentOfEducation" xlink:to="osbc_PercentageOfOutstandingPrincipalAmountOfLoansGuaranteedByUsDepartmentOfEducation_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_PercentageOfOutstandingPrincipalAmountOfLoansGuaranteedByUsDepartmentOfEducation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Reflects percentage of outstanding principal amount of loans guaranteed by US Department of Education.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_PercentageOfOutstandingPrincipalAmountOfLoansGuaranteedByUsDepartmentOfEducation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Percentage of outstanding principal amount of loans guaranteed by US Department of Education</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation" xlink:label="osbc_PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation" xlink:to="osbc_PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the percent of insured loans used as base for loans guaranteed by US Department of Education.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Percent Of Insured Loans Used As Base For Loans Guaranteed By U S Department Of Education</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Percent of insured loan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskPercentage1" xlink:label="us-gaap_ConcentrationRiskPercentage1" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskPercentage1" xlink:to="us-gaap_ConcentrationRiskPercentage1_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration Risk, Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Percentage of concentration risk</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConcentrationRiskPercentage1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Credit risk as a percentage of benchmark</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleRestricted" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRestricted" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtSecuritiesAvailableForSaleRestricted" xlink:to="us-gaap_DebtSecuritiesAvailableForSaleRestricted_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRestricted_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities Pledged as Collateral</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtSecuritiesAvailableForSaleRestricted_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities pledged to secure deposits and for other purposes</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, Amortized Cost Basis, Fiscal Year Maturity [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Available-for-Sale, Amortized Cost</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, Next Twelve Months, Amortized Cost Basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due in one year or less</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, Year Two Through Five, Amortized Cost Basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due after one year through five years</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Amortized Cost Basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due after five years through ten years</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, after Ten Years, Amortized Cost Basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due after ten years</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis" xlink:to="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortized cost of debt securities categorized neither as held-to-maturity nor trading. This item represents the total amortized cost of all debt securities grouped by maturity dates, excluding the securities with no single maturity date.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Debt Maturities, before Securities without Single Maturity Date, Amortized Cost Basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt securities excluding securities not due at a single maturity date</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Amortized Cost Basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateAmortizedCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities not due at a single maturity date</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract" xlink:to="osbc_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">No definition available.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Securities Debt Maturities Amortized Cost, Weighted Average Yield [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Available-for-Sale, Weighted Average Yield</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield" xlink:to="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the weighted average yield of available-for-sale debt securities maturing in the next fiscal year following the latest fiscal year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Securities Debt Maturities within One Year Amortized Cost, Weighted Average Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due in one year or less (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCostWeightedAverageYield" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCostWeightedAverageYield" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the weighted average yield of available-for-sale debt securities maturing in the second fiscal year through the fifth fiscal year following the latest fiscal year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Securities, Debt Maturities, after One Through Five Years Amortized Cost, Weighted Average Yield</label>
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    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield" xlink:to="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the weighted average yield of available-for-sale debt securities maturing in the sixth fiscal year through the tenth fiscal year following the latest fiscal year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Securities, Debt Maturities, after Five Through Ten Years Amortized Cost, Weighted Average Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due after five years through ten years (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield" xlink:to="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the weighted average yield of available-for-sale debt securities maturing after the tenth fiscal year following the latest fiscal year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Securities, Debt Maturities, after Ten Years Amortized Cost, Weighted Average Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due after ten years (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield" xlink:to="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the weighted average yield of available-for-sale debt securities maturing after the tenth rolling twelve months following the latest balance sheet presented. This item represents the weighted average yield of all debt securities grouped by maturity dates, excluding the securities with no single maturity date.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Debt Maturities, before Securities without Single Maturity Date, Weighted Average Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt securities (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield" xlink:to="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the weighted average yield of available-for-sale debt securities that do not have a single maturity date and which the entity has decided to disclose separately rather than allocating the cost over several maturity groupings.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Securities, Debt Maturities, without Single Maturity Date, Weighted Average Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities not due at a single maturity date, Weighted Average Yield (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleSecuritiesWeightedAverageYield" xlink:label="osbc_AvailableForSaleSecuritiesWeightedAverageYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleSecuritiesWeightedAverageYield" xlink:to="osbc_AvailableForSaleSecuritiesWeightedAverageYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleSecuritiesWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the weighted average yield of available-for-sale securities.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleSecuritiesWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Securities, Weighted Average Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AvailableForSaleSecuritiesWeightedAverageYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesFairValueAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Available-for-Sale, Fair Value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due in one year or less</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due after one year through five years</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due after five years through ten years</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Due after ten years</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue" xlink:to="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair value of debt securities categorized neither as held-to-maturity nor trading. This item represents the total fair value of all debt securities grouped by maturity dates, excluding the securities with no single maturity date.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available For Sale Debt Maturities, before Securities without Single Maturity Date, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt securities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Debt Maturities, without Single Maturity Date, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities not due at a single maturity date</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract" xlink:to="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Continuous Unrealized Loss Position [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Available-for-Sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionQualitativeDisclosureAbstract" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionQualitativeDisclosureAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionQualitativeDisclosureAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Continuous Unrealized Loss Position, Qualitative Disclosure [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionQualitativeDisclosureAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Available-for-Sale, Number of Securities</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AvailableForSaleSecuritiesInUnrealizedLossPositionLessThan12MonthsQualitativeDisclosureNumberOfPositions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the number of investment positions of securities categorized neither as held-to-maturity nor trading securities, that have been in a loss position for less than twelve months.</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLossAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Available-for-Sale, Unrealized Losses</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available for Sale Securities Continuous Unrealized Loss Position Less than 12 Months Aggregate Losses Accumulated in Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Less than 12 months in an unrealized loss position</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Greater than 12 months in an unrealized loss position</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available for Sale Securities Continuous Unrealized Loss Position Aggregate Losses Accumulated in Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionAccumulatedLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract" xlink:to="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValueAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Available-for-Sale, Fair Value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Less than 12 months in an unrealized loss position</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Continuous Unrealized Loss Position, Twelve Months or Longer, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Greater than 12 months in an unrealized loss position</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue" xlink:to="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable" xlink:to="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Available-for-sale Securities [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:to="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Available-for-sale Securities [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from sale and gross realized gains and losses on sale of securities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossRealizedGains" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedGains" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedGains_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Gross Realized Gains</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedGains_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Gross realized gains on securities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Available-for-sale Securities, Gross Realized Gain (Loss)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_AvailableForSaleSecuritiesGrossRealizedGainLossNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities (losses) gains, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EffectiveIncomeTaxRateContinuingOperations" xlink:label="us-gaap_EffectiveIncomeTaxRateContinuingOperations" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableGrossCarryingAmount" xlink:label="us-gaap_LoansAndLeasesReceivableGrossCarryingAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableGrossCarryingAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total loans, gross</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LoansAndLeasesReceivableDeferredIncomeExpenseNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable Deferred Income (Expense), Net</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_LoansAndLeasesReceivableExcludingPCILoansNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount, excluding PCI loans, before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LoansAndLeasesReceivableExcludingPCILoansNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Excluding P C I Loans, Net of Deferred Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="osbc_LoansAndLeasesReceivableExcludingPCILoansNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total loans, excluding PCI loans</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome" xlink:to="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount before allowance and after deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans and purchased credit impaired loans. Excludes loans and leases covered under loss sharing agreements.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Including Purchased Credit Impaired Loans, Net of Deferred Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total Loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total Loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskByTypeAxis" xlink:label="us-gaap_ConcentrationRiskByTypeAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskByTypeAxis" xlink:to="us-gaap_ConcentrationRiskByTypeAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskByTypeAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration Risk Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConcentrationRiskTypeDomain" xlink:label="us-gaap_ConcentrationRiskTypeDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConcentrationRiskTypeDomain" xlink:to="us-gaap_ConcentrationRiskTypeDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConcentrationRiskTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration Risk Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConcentrationRiskTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Concentration Risk Type [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CustomerConcentrationRiskMember" xlink:label="us-gaap_CustomerConcentrationRiskMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CustomerConcentrationRiskMember" xlink:to="us-gaap_CustomerConcentrationRiskMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CustomerConcentrationRiskMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Customer Concentration Risk [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CustomerConcentrationRiskMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Customer concentration risk</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_IncreaseInLoans" xlink:label="osbc_IncreaseInLoans" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_IncreaseInLoans" xlink:to="osbc_IncreaseInLoans_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_IncreaseInLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of increase in loan balance over previous year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_IncreaseInLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase In Loans</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_IncreaseInLoans_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Growth in loan balance</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio" xlink:label="osbc_LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio" xlink:to="osbc_LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the percentage of total portfolio that is represented by a particular financial receivable category.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable as Percentage of Aggregate Portfolio</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans receivable as a percentage of total portfolio</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivablesPastDueTable" xlink:label="us-gaap_ScheduleOfFinancingReceivablesPastDueTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFinancingReceivablesPastDueTable" xlink:to="us-gaap_ScheduleOfFinancingReceivablesPastDueTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfFinancingReceivablesPastDueTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Financing Receivables Past Due [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems" xlink:to="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Recorded Investment, Past Due [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDueLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Aged analysis of past due loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentPastDue" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentPastDue" xlink:to="us-gaap_FinancingReceivableRecordedInvestmentPastDue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Recorded Investment, Past Due</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentPastDue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total Past Due</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentCurrent" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentCurrent" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentCurrent" xlink:to="us-gaap_FinancingReceivableRecordedInvestmentCurrent_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentCurrent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Recorded Investment, Current</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentCurrent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Current</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus" xlink:to="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Recorded Investment, Nonaccrual Status</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Nonaccrual</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue" xlink:to="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">definition</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Including Purchased Credit Impaired Loans Net of Deferred Income, Past Due</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total Loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing" xlink:label="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing" xlink:to="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Recorded Investment, 90 Days Past Due and Still Accruing</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableRecordedInvestment90DaysPastDueAndStillAccruing_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Recorded Investment 90 days or Greater Past Due and Accruing</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xlink:label="us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable" xlink:to="us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfFinancingReceivableRecordedInvestmentCreditQualityIndicatorTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Financing Receivable, Recorded Investment, Credit Quality Indicator [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentLineItems" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentLineItems" xlink:to="us-gaap_FinancingReceivableRecordedInvestmentLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Recorded Investment [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans by risk rating</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing" xlink:label="osbc_OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing" xlink:to="osbc_OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The outstanding loan commitment to be included in credit quality indicator analysis.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Outstanding Loan Commitments Threshold for Credit Quality Categorizing</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loan commitment for inclusion in credit quality analysis</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherRealEstateAndForeclosedAssetsAbstract" xlink:label="us-gaap_OtherRealEstateAndForeclosedAssetsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherRealEstateAndForeclosedAssetsAbstract" xlink:to="us-gaap_OtherRealEstateAndForeclosedAssetsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherRealEstateAndForeclosedAssetsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Real Estate, Foreclosed Assets, and Repossessed Assets [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherRealEstateAndForeclosedAssetsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Repossessed and foreclosed assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageLoansInProcessOfForeclosureAmount" xlink:label="us-gaap_MortgageLoansInProcessOfForeclosureAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MortgageLoansInProcessOfForeclosureAmount" xlink:to="us-gaap_MortgageLoansInProcessOfForeclosureAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MortgageLoansInProcessOfForeclosureAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Loans in Process of Foreclosure, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MortgageLoansInProcessOfForeclosureAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage loans in process of foreclosure</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfImpairedFinancingReceivableTable" xlink:label="us-gaap_ScheduleOfImpairedFinancingReceivableTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfImpairedFinancingReceivableTable" xlink:to="us-gaap_ScheduleOfImpairedFinancingReceivableTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfImpairedFinancingReceivableTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Impaired Financing Receivable [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis" xlink:label="us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis" xlink:to="us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Receivable Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ReceivableTypeDomain" xlink:label="us-gaap_ReceivableTypeDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ReceivableTypeDomain" xlink:to="us-gaap_ReceivableTypeDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ReceivableTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Receivable Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ReceivableTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Receivable [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember" xlink:label="osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember" xlink:to="osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to commercial real estate occupied by owner, for general purpose.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial Real Estate Owner Occupied General Purpose Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Owner occupied general purpose</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember" xlink:label="osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember" xlink:to="osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to commercial real estate occupied by owner, for special purpose includes loans collateralized by property types such as gas stations, health and fitness centers, golf courses, restaurants, and medical office buildings.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial Real Estate Owner Occupied Special Purpose Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Owner occupied special purpose</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember" xlink:label="osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember" xlink:to="osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to commercial real estate occupied by non-owner, for general purpose include credits that are collateralized by office, warehouse, and industrial properties.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial Real Estate Non Owner Occupied General Purpose Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Non-owner occupied general purpose</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember" xlink:label="osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember" xlink:to="osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to commercial real estate occupied by non-owner, for special purpose.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial Real Estate Non Owner Occupied Special Purpose Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Non-owner occupied special purpose</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommercialRealEstateRetailPropertiesLoanMember" xlink:label="osbc_CommercialRealEstateRetailPropertiesLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommercialRealEstateRetailPropertiesLoanMember" xlink:to="osbc_CommercialRealEstateRetailPropertiesLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommercialRealEstateRetailPropertiesLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to commercial real estate retail properties.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommercialRealEstateRetailPropertiesLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial Real Estate Retail Properties Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommercialRealEstateRetailPropertiesLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Retail properties</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ConstructionRealEstateOtherReceivableMember" xlink:label="osbc_ConstructionRealEstateOtherReceivableMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ConstructionRealEstateOtherReceivableMember" xlink:to="osbc_ConstructionRealEstateOtherReceivableMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ConstructionRealEstateOtherReceivableMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to construction real estate which includes other construction real estate loan.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ConstructionRealEstateOtherReceivableMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Construction Real Estate Other Receivable [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ConstructionRealEstateOtherReceivableMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">All other</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ResidentialInvestorLoanMember" xlink:label="osbc_ResidentialInvestorLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ResidentialInvestorLoanMember" xlink:to="osbc_ResidentialInvestorLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ResidentialInvestorLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to investor loan on residential real estate.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ResidentialInvestorLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Residential Investor Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ResidentialInvestorLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investor</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ResidentialOwnerOccupiedLoanMember" xlink:label="osbc_ResidentialOwnerOccupiedLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ResidentialOwnerOccupiedLoanMember" xlink:to="osbc_ResidentialOwnerOccupiedLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ResidentialOwnerOccupiedLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to residential owner occupied real estate.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ResidentialOwnerOccupiedLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Residential Owner Occupied Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ResidentialOwnerOccupiedLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Owner occupied</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ResidentialRevolvingAndJuniorLiensLoanMember" xlink:label="osbc_ResidentialRevolvingAndJuniorLiensLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ResidentialRevolvingAndJuniorLiensLoanMember" xlink:to="osbc_ResidentialRevolvingAndJuniorLiensLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ResidentialRevolvingAndJuniorLiensLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to residential revolving and junior lien real estate.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ResidentialRevolvingAndJuniorLiensLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Residential Revolving And Junior Liens Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ResidentialRevolvingAndJuniorLiensLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Revolving and junior liens</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableImpairedLineItems" xlink:label="us-gaap_FinancingReceivableImpairedLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableImpairedLineItems" xlink:to="us-gaap_FinancingReceivableImpairedLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableImpairedLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Impaired [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableImpairedLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Analysis of impaired loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract" xlink:label="us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract" xlink:to="us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Recorded Investment [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableRecordedInvestmentAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Recorded Investment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment" xlink:to="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, with No Related Allowance, Recorded Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With no related allowance recorded</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment" xlink:to="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, with Related Allowance, Recorded Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With an allowance recorded</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableRecordedInvestment" xlink:label="us-gaap_ImpairedFinancingReceivableRecordedInvestment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableRecordedInvestment" xlink:to="us-gaap_ImpairedFinancingReceivableRecordedInvestment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Recorded Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_ImpairedFinancingReceivableRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total impaired loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract" xlink:label="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract" xlink:to="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Unpaid Principal Balance [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalanceAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Unpaid Principal Balance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance" xlink:to="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, with No Related Allowance, Unpaid Principal Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceUnpaidPrincipalBalance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With no related allowance recorded</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance" xlink:to="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, with Related Allowance, Unpaid Principal Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceUnpaidPrincipalBalance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With an allowance recorded</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance" xlink:label="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance" xlink:to="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Unpaid Principal Balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_ImpairedFinancingReceivableUnpaidPrincipalBalance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total impaired loans</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ImpairedFinancingReceivableRelatedAllowanceAbstract" xlink:label="osbc_ImpairedFinancingReceivableRelatedAllowanceAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ImpairedFinancingReceivableRelatedAllowanceAbstract" xlink:to="osbc_ImpairedFinancingReceivableRelatedAllowanceAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ImpairedFinancingReceivableRelatedAllowanceAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable Related Allowance [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ImpairedFinancingReceivableRelatedAllowanceAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Related Allowance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableRelatedAllowance" xlink:label="us-gaap_ImpairedFinancingReceivableRelatedAllowance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableRelatedAllowance" xlink:to="us-gaap_ImpairedFinancingReceivableRelatedAllowance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableRelatedAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Related Allowance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableRelatedAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With an allowance recorded</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableRelatedAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Valuation allowance</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommercialRealEstateFarmLoanMember" xlink:label="osbc_CommercialRealEstateFarmLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommercialRealEstateFarmLoanMember" xlink:to="osbc_CommercialRealEstateFarmLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommercialRealEstateFarmLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to commercial real estate farm.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommercialRealEstateFarmLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial Real Estate Farm Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommercialRealEstateFarmLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Farm</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ConstructionRealEstateCommercialSpeculativeLoanMember" xlink:label="osbc_ConstructionRealEstateCommercialSpeculativeLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ConstructionRealEstateCommercialSpeculativeLoanMember" xlink:to="osbc_ConstructionRealEstateCommercialSpeculativeLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ConstructionRealEstateCommercialSpeculativeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to commercial speculative construction real estate.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ConstructionRealEstateCommercialSpeculativeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Construction Real Estate Commercial Speculative Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ConstructionRealEstateCommercialSpeculativeLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial speculative</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableAverageRecordedInvestmentAbstract" xlink:label="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestmentAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestmentAbstract" xlink:to="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestmentAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestmentAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Average Recorded Investment [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestmentAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Average Recorded Investment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment" xlink:to="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, with No Related Allowance, Average Recorded Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceAverageRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With no related allowance recorded</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment" xlink:to="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, with Related Allowance, Average Recorded Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceAverageRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With an allowance recorded</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment" xlink:label="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment" xlink:to="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Average Recorded Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_ImpairedFinancingReceivableAverageRecordedInvestment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total impaired loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethodAbstract" xlink:label="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethodAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethodAbstract" xlink:to="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethodAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethodAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Interest Income, Accrual Method [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethodAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Income Recognized</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod" xlink:to="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, with No Related Allowance, Interest Income, Accrual Method</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableWithNoRelatedAllowanceInterestIncomeAccrualMethod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With no related allowance recorded</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod" xlink:to="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, with Related Allowance, Interest Income, Accrual Method</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ImpairedFinancingReceivableWithRelatedAllowanceInterestIncomeAccrualMethod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">With an allowance recorded</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod" xlink:label="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod" xlink:to="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable, Interest Income, Accrual Method</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_ImpairedFinancingReceivableInterestIncomeAccrualMethod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total impaired loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable" xlink:label="us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable" xlink:to="us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfFinancingReceivableTroubledDebtRestructuringsTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Financing Receivable, Troubled Debt Restructurings [Table]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ConstructionRealEstatePortfolioSegmentMember" xlink:label="osbc_ConstructionRealEstatePortfolioSegmentMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ConstructionRealEstatePortfolioSegmentMember" xlink:to="osbc_ConstructionRealEstatePortfolioSegmentMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ConstructionRealEstatePortfolioSegmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Portfolio segment of the company's total financing receivables related to construction real estate.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ConstructionRealEstatePortfolioSegmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Construction Real Estate Portfolio Segment [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ConstructionRealEstatePortfolioSegmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real estate - construction</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalCreditAssessmentAxis" xlink:label="us-gaap_InternalCreditAssessmentAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InternalCreditAssessmentAxis" xlink:to="us-gaap_InternalCreditAssessmentAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InternalCreditAssessmentAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Internal Credit Assessment [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InternalCreditAssessmentDomain" xlink:label="us-gaap_InternalCreditAssessmentDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InternalCreditAssessmentDomain" xlink:to="us-gaap_InternalCreditAssessmentDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InternalCreditAssessmentDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Internal Credit Assessment [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InternalCreditAssessmentDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Internal Credit Assessment [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OthersMember" xlink:label="osbc_OthersMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OthersMember" xlink:to="osbc_OthersMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OthersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents financing receivables restructured to others.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OthersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Others [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OthersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_HomeAffordableModificationProgramMember" xlink:label="osbc_HomeAffordableModificationProgramMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_HomeAffordableModificationProgramMember" xlink:to="osbc_HomeAffordableModificationProgramMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_HomeAffordableModificationProgramMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents financing receivables restructured under Home Affordable Modification Program (HAMP).</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_HomeAffordableModificationProgramMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Home Affordable Modification Program [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_HomeAffordableModificationProgramMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">HAMP</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_InterestRateConcessionBelowNormalMarketMember" xlink:label="osbc_InterestRateConcessionBelowNormalMarketMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_InterestRateConcessionBelowNormalMarketMember" xlink:to="osbc_InterestRateConcessionBelowNormalMarketMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_InterestRateConcessionBelowNormalMarketMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the financing receivables restructured to an interest rate concession below the normal market.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_InterestRateConcessionBelowNormalMarketMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Rate Concession Below Normal Market [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_InterestRateConcessionBelowNormalMarketMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Rate</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsLineItems" xlink:label="us-gaap_FinancingReceivableModificationsLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableModificationsLineItems" xlink:to="us-gaap_FinancingReceivableModificationsLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableModificationsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Modifications [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableModificationsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Troubled debt restructurings - modified during the period</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsNumberOfContracts2" xlink:label="us-gaap_FinancingReceivableModificationsNumberOfContracts2" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableModificationsNumberOfContracts2" xlink:to="us-gaap_FinancingReceivableModificationsNumberOfContracts2_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableModificationsNumberOfContracts2_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Modifications, Number of Contracts</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableModificationsNumberOfContracts2_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase"># of contracts</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2" xlink:label="us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2" xlink:to="us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Modifications, Pre-Modification Recorded Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableModificationsPreModificationRecordedInvestment2_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pre-modification recorded investment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2" xlink:label="us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2" xlink:to="us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Modifications, Post-Modification Recorded Investment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableModificationsPostModificationRecordedInvestment2_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Post-modification recorded investment</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract" xlink:label="osbc_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract" xlink:to="osbc_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Modifications, Subsequent Payment Default [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">TDR's defaulted</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1" xlink:label="us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1" xlink:to="us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Modifications, Subsequent Default, Number of Contracts</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase"># of contracts</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoanAndLeaseReceivablesImpairedAbstract" xlink:label="us-gaap_LoanAndLeaseReceivablesImpairedAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoanAndLeaseReceivablesImpairedAbstract" xlink:to="us-gaap_LoanAndLeaseReceivablesImpairedAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoanAndLeaseReceivablesImpairedAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loan and Lease Receivables, Impaired [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoanAndLeaseReceivablesImpairedAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other information</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend" xlink:label="us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend" xlink:to="us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans and Leases Receivable, Impaired, Commitment to Lend</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansAndLeasesReceivableImpairedCommitmentToLend_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commitments to lend to borrowers whose loans were classified as impaired</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward" xlink:to="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldMovementScheduleRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield Movement Schedule [Roll Forward]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield" xlink:to="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Beginning balance</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield" xlink:to="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of non-accretable discount on acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Non-Accretable Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Beginning balance</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield" xlink:to="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of accretable and non-accretable yield on acquired loans not accounted for as debt securities with evidence of deterioration of credit quality.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable and Non-Accretable Yield</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Beginning balance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions" xlink:to="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certain Loans Acquired in Transfer Not Accounted for as Debt Securities, Accretable Yield, Additions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableYieldAdditions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Purchases</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYieldAdditions" xlink:label="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYieldAdditions" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllowanceForLoanAndLeaseLossesRollForward" xlink:to="us-gaap_AllowanceForLoanAndLeaseLossesRollForward_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Allowance for Loan and Lease Losses [Roll Forward]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Allowance for loan losses:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs" xlink:to="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Allowance for Loan and Lease Losses, Write-offs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossesWriteOffs_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Charge-offs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts" xlink:to="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Allowance for Loan and Lease Loss, Recovery of Bad Debts</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AllowanceForLoanAndLeaseLossRecoveryOfBadDebts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Recoveries</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1" xlink:to="us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesIndividuallyEvaluatedForImpairment1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance: Individually evaluated for impairment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment" xlink:to="us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossesCollectivelyEvaluatedForImpairment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance: Collectively evaluated for impairment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract" xlink:to="us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Allowance for Credit Loss, Additional Information [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableAllowanceForCreditLossAdditionalInformationAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment" xlink:label="us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment" xlink:to="us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Individually Evaluated for Impairment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableIndividuallyEvaluatedForImpairment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance: Individually evaluated for impairment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment" xlink:label="us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment" xlink:to="us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable, Collectively Evaluated for Impairment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableCollectivelyEvaluatedForImpairment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance: Collectively evaluated for impairment</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherRealEstateRollForward" xlink:label="us-gaap_OtherRealEstateRollForward" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherRealEstateRollForward" xlink:to="us-gaap_OtherRealEstateRollForward_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherRealEstateRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Real Estate [Roll Forward]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherRealEstateRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Activity in the other real estate owned (OREO) portfolio, net of valuation reserve</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateAcquisitionsThroughForeclosures" xlink:label="us-gaap_RealEstateAcquisitionsThroughForeclosures" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateAcquisitionsThroughForeclosures" xlink:to="us-gaap_RealEstateAcquisitionsThroughForeclosures_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateAcquisitionsThroughForeclosures_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">SEC Schedule III, Real Estate, Acquisitions Through Foreclosures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RealEstateAcquisitionsThroughForeclosures_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property additions</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateImprovements" xlink:label="us-gaap_RealEstateImprovements" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateImprovements" xlink:to="us-gaap_RealEstateImprovements_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateImprovements_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">SEC Schedule III, Real Estate, Improvements</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RealEstateImprovements_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property improvements</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RealEstateCostOfRealEstateSoldNetOfGainLoss" xlink:label="osbc_RealEstateCostOfRealEstateSoldNetOfGainLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_RealEstateCostOfRealEstateSoldNetOfGainLoss" xlink:to="osbc_RealEstateCostOfRealEstateSoldNetOfGainLoss_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_RealEstateCostOfRealEstateSoldNetOfGainLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The amount of real estate sold during the period net of gains (losses) on sale.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RealEstateCostOfRealEstateSoldNetOfGainLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Cost of Real Estate Sold, Net of Gain (Loss)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_RealEstateCostOfRealEstateSoldNetOfGainLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Less: Property disposals, net of gains/losses</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment" xlink:label="osbc_RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment" xlink:to="osbc_RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of the increase in the real estate owned valuation allowance, net of miscellaneous adjustments, that is charged against earnings in the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Owned Valuation Allowance Provision Net of Adjustment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="osbc_RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Less: Period valuation adjustments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateOwnedValuationAllowanceRollForward" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceRollForward" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateOwnedValuationAllowanceRollForward" xlink:to="us-gaap_RealEstateOwnedValuationAllowanceRollForward_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Owned Valuation Allowance [Roll Forward]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Activity in the valuation allowance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateOwnedValuationAllowance" xlink:label="us-gaap_RealEstateOwnedValuationAllowance" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateOwnedValuationAllowance" xlink:to="us-gaap_RealEstateOwnedValuationAllowance_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateOwnedValuationAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Owned, Valuation Allowance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_RealEstateOwnedValuationAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Balance at end of period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_RealEstateOwnedValuationAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Balance at beginning of period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RealEstateOwnedValuationAllowance_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">OREO Valuation allowance</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateOwnedValuationAllowanceAmountsApplied" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceAmountsApplied" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateOwnedValuationAllowanceAmountsApplied" xlink:to="us-gaap_RealEstateOwnedValuationAllowanceAmountsApplied_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceAmountsApplied_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Owned, Valuation Allowance, Amounts Applied</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_RealEstateOwnedValuationAllowanceAmountsApplied_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Reductions taken on sales</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RealEstateOtherDeductions" xlink:label="us-gaap_RealEstateOtherDeductions" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RealEstateOtherDeductions" xlink:to="us-gaap_RealEstateOtherDeductions_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RealEstateOtherDeductions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">SEC Schedule III, Real Estate, Other Deductions</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RealEstateOtherDeductions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other adjustments</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OtherRealEstateOwnedExpensesRelatedToForeclosedAssetsAbstract" xlink:label="osbc_OtherRealEstateOwnedExpensesRelatedToForeclosedAssetsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OtherRealEstateOwnedExpensesRelatedToForeclosedAssetsAbstract" xlink:to="osbc_OtherRealEstateOwnedExpensesRelatedToForeclosedAssetsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OtherRealEstateOwnedExpensesRelatedToForeclosedAssetsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Real Estate Owned Expenses Related to Foreclosed Assets [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OtherRealEstateOwnedExpensesRelatedToForeclosedAssetsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Expenses related to foreclosed assets, net of lease revenue</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RealEstateAcquiredThroughForeclosureOperatingExpenses" xlink:label="osbc_RealEstateAcquiredThroughForeclosureOperatingExpenses" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_RealEstateAcquiredThroughForeclosureOperatingExpenses" xlink:to="osbc_RealEstateAcquiredThroughForeclosureOperatingExpenses_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_RealEstateAcquiredThroughForeclosureOperatingExpenses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of operating expenses recognized during the period for real estate assets acquired through settlement or foreclosure.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RealEstateAcquiredThroughForeclosureOperatingExpenses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Acquired Through Foreclosure Operating Expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_RealEstateAcquiredThroughForeclosureOperatingExpenses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating expenses</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_LeaseRevenueForOtherRealEstate" xlink:label="osbc_LeaseRevenueForOtherRealEstate" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_LeaseRevenueForOtherRealEstate" xlink:to="osbc_LeaseRevenueForOtherRealEstate_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_LeaseRevenueForOtherRealEstate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Lease revenue for other real estate owned.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LeaseRevenueForOtherRealEstate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Lease Revenue for Other Real Estate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_LeaseRevenueForOtherRealEstate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Less: Lease revenue</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ForeclosedRealEstateExpenseNetOfLeaseRevenue" xlink:label="osbc_ForeclosedRealEstateExpenseNetOfLeaseRevenue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ForeclosedRealEstateExpenseNetOfLeaseRevenue" xlink:to="osbc_ForeclosedRealEstateExpenseNetOfLeaseRevenue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ForeclosedRealEstateExpenseNetOfLeaseRevenue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of expense recognized during the period for real estate assets acquired through foreclosure, net of lease revenue.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ForeclosedRealEstateExpenseNetOfLeaseRevenue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Foreclosed Real Estate Expense Net of Lease Revenue</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="osbc_ForeclosedRealEstateExpenseNetOfLeaseRevenue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Expenses related to OREO, net of lease revenue</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LandMember" xlink:label="us-gaap_LandMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LandMember" xlink:to="us-gaap_LandMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LandMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Land [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LandMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Land</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LeaseholdImprovementsMember" xlink:label="us-gaap_LeaseholdImprovementsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseholdImprovementsMember" xlink:to="us-gaap_LeaseholdImprovementsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Leasehold Improvements [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LeaseholdImprovementsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Leasehold improvements</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PropertyPlantAndEquipmentGross" xlink:label="us-gaap_PropertyPlantAndEquipmentGross" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PropertyPlantAndEquipmentGross" xlink:to="us-gaap_PropertyPlantAndEquipmentGross_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Property, Plant and Equipment, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PropertyPlantAndEquipmentGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cost</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment" xlink:to="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AccumulatedDepreciationDepletionAndAmortizationPropertyPlantAndEquipment_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Accumulated Depreciation/Amortization</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepositsSavingsDeposits" xlink:label="us-gaap_DepositsSavingsDeposits" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepositsSavingsDeposits" xlink:to="us-gaap_DepositsSavingsDeposits_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DepositsSavingsDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposits, Savings Deposits</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DepositsSavingsDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Savings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepositsNegotiableOrderOfWithdrawalNOW" xlink:label="us-gaap_DepositsNegotiableOrderOfWithdrawalNOW" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepositsNegotiableOrderOfWithdrawalNOW" xlink:to="us-gaap_DepositsNegotiableOrderOfWithdrawalNOW_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DepositsNegotiableOrderOfWithdrawalNOW_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposits, Negotiable Order of Withdrawal (NOW)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DepositsNegotiableOrderOfWithdrawalNOW_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">NOW accounts</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepositsMoneyMarketDeposits" xlink:label="us-gaap_DepositsMoneyMarketDeposits" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepositsMoneyMarketDeposits" xlink:to="us-gaap_DepositsMoneyMarketDeposits_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DepositsMoneyMarketDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposits, Money Market Deposits</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DepositsMoneyMarketDeposits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Money market accounts</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositsLessThan100000" xlink:label="us-gaap_TimeDepositsLessThan100000" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimeDepositsLessThan100000" xlink:to="us-gaap_TimeDepositsLessThan100000_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TimeDepositsLessThan100000_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposits, Less than $100,000</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TimeDepositsLessThan100000_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certificates of deposit of less than $100,000</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TimeDeposits100000To250000" xlink:label="osbc_TimeDeposits100000To250000" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TimeDeposits100000To250000" xlink:to="osbc_TimeDeposits100000To250000_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TimeDeposits100000To250000_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations between $100,000 and $250,000.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TimeDeposits100000To250000_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposits, $100,000 to $250,000</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TimeDeposits100000To250000_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certificates of deposit of $100,000 up to $250,000</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TimeDeposits250000OrMore" xlink:label="osbc_TimeDeposits250000OrMore" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TimeDeposits250000OrMore" xlink:to="osbc_TimeDeposits250000OrMore_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TimeDeposits250000OrMore_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The aggregate amount of domestic and foreign time deposit liabilities (including certificates of deposits, individual retirement accounts and open accounts) in denominations of $250,000 or more.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TimeDeposits250000OrMore_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposits, $250,000 or More</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TimeDeposits250000OrMore_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Certificates of deposit of $250,000 or more</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow" xlink:label="osbc_DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow" xlink:to="osbc_DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of interest bearing deposits with no stated maturity, which may include passbook and statement savings accounts and money-market deposit accounts (MMDAs) and deposits in accounts that offer many of the same services as checking accounts although transactions may be somewhat more limited, share some of the characteristics of a money market fund and are insured by the Federal government, also known as money market accounts. Also includes amount of deposits in interest-bearing transaction accounts at banks or savings and loans, that are restricted in regard to ownership and can usually only be held by individuals, nonprofit entities and governments. Negotiable order of withdrawal accounts differ from money market demand accounts as they typically have higher reserve requirements and no limit on the number of checks that can be written.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposits, Savings, Money Market Deposits and Negotiable Order of Withdrawal (NOW)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Savings, NOW and money market</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositLiabilitiesDomesticByComponentAbstract" xlink:label="us-gaap_InterestBearingDepositLiabilitiesDomesticByComponentAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestBearingDepositLiabilitiesDomesticByComponentAbstract" xlink:to="us-gaap_InterestBearingDepositLiabilitiesDomesticByComponentAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestBearingDepositLiabilitiesDomesticByComponentAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest-bearing Deposit Liabilities, Domestic, by Component [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestBearingDepositLiabilitiesDomesticByComponentAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Brokered certificates</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDomesticDepositBrokered" xlink:label="us-gaap_InterestBearingDomesticDepositBrokered" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestBearingDomesticDepositBrokered" xlink:to="us-gaap_InterestBearingDomesticDepositBrokered_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestBearingDomesticDepositBrokered_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest-bearing Domestic Deposit, Brokered</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestBearingDomesticDepositBrokered_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Brokered certificates of deposit</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DepositLiabilitiesWithAbnormalTerms" xlink:label="us-gaap_DepositLiabilitiesWithAbnormalTerms" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DepositLiabilitiesWithAbnormalTerms" xlink:to="us-gaap_DepositLiabilitiesWithAbnormalTerms_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DepositLiabilitiesWithAbnormalTerms_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposit Liabilities with Abnormal Terms</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DepositLiabilitiesWithAbnormalTerms_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposits held by senior officers and directors, including their related interests</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositsByMaturityAbstract" xlink:label="us-gaap_TimeDepositsByMaturityAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimeDepositsByMaturityAbstract" xlink:to="us-gaap_TimeDepositsByMaturityAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TimeDepositsByMaturityAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposits, Fiscal Year Maturity [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TimeDepositsByMaturityAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposit Maturities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesYearOne" xlink:label="us-gaap_TimeDepositMaturitiesYearOne" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimeDepositMaturitiesYearOne" xlink:to="us-gaap_TimeDepositMaturitiesYearOne_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TimeDepositMaturitiesYearOne_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposit Maturities, Next Twelve Months</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TimeDepositMaturitiesYearOne_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2019</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesYearTwo" xlink:label="us-gaap_TimeDepositMaturitiesYearTwo" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimeDepositMaturitiesYearTwo" xlink:to="us-gaap_TimeDepositMaturitiesYearTwo_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TimeDepositMaturitiesYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposit Maturities, Year Two</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TimeDepositMaturitiesYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2020</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesYearThree" xlink:label="us-gaap_TimeDepositMaturitiesYearThree" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimeDepositMaturitiesYearThree" xlink:to="us-gaap_TimeDepositMaturitiesYearThree_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TimeDepositMaturitiesYearThree_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposit Maturities, Year Three</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TimeDepositMaturitiesYearThree_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2021</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesYearFour" xlink:label="us-gaap_TimeDepositMaturitiesYearFour" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimeDepositMaturitiesYearFour" xlink:to="us-gaap_TimeDepositMaturitiesYearFour_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TimeDepositMaturitiesYearFour_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposit Maturities, Year Four</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TimeDepositMaturitiesYearFour_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2022</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TimeDepositMaturitiesYearFive" xlink:label="us-gaap_TimeDepositMaturitiesYearFive" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TimeDepositMaturitiesYearFive" xlink:to="us-gaap_TimeDepositMaturitiesYearFive_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TimeDepositMaturitiesYearFive_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Time Deposit Maturities, Year Five</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TimeDepositMaturitiesYearFive_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2023</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTable" xlink:label="us-gaap_DebtInstrumentTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentTable" xlink:to="us-gaap_DebtInstrumentTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Long-term Debt Instruments [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentAxis" xlink:label="us-gaap_DebtInstrumentAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentAxis" xlink:to="us-gaap_DebtInstrumentAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentNameDomain" xlink:label="us-gaap_DebtInstrumentNameDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentNameDomain" xlink:to="us-gaap_DebtInstrumentNameDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument, Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember" xlink:to="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Sold Under Agreements To Repurchase [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SecuritiesSoldUnderAgreementsToRepurchaseMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities sold under repurchase agreements</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesMember" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FederalHomeLoanBankAdvancesMember" xlink:to="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Advances [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FederalHomeLoanBankAdvancesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FHLBC advances</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NotesPayableToBanksMember" xlink:label="us-gaap_NotesPayableToBanksMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NotesPayableToBanksMember" xlink:to="us-gaap_NotesPayableToBanksMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NotesPayableToBanksMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Notes Payable To Banks [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NotesPayableToBanksMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Notes payable and other borrowings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="us-gaap_DebtInstrumentLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentLineItems" xlink:to="us-gaap_DebtInstrumentLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Borrowings</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DebtInstrumentLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Junior subordinated debentures</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtLongtermAndShorttermCombinedAmount" xlink:label="us-gaap_DebtLongtermAndShorttermCombinedAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtLongtermAndShorttermCombinedAmount" xlink:to="us-gaap_DebtLongtermAndShorttermCombinedAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtLongtermAndShorttermCombinedAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt, Long-term and Short-term, Combined Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtLongtermAndShorttermCombinedAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total borrowings</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_DebtLongtermAndShorttermCombinedAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DebtInstrumentMaturityTerm" xlink:label="osbc_DebtInstrumentMaturityTerm" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DebtInstrumentMaturityTerm" xlink:to="osbc_DebtInstrumentMaturityTerm_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DebtInstrumentMaturityTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the maturity term of the debt instrument.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DebtInstrumentMaturityTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument Maturity Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DebtInstrumentMaturityTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Maturity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements" xlink:label="us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements" xlink:to="us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pledged Financial Instruments, Not Separately Reported, Securities for Repurchase Agreements</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PledgedFinancialInstrumentsNotSeparatelyReportedSecuritiesForRepurchaseAgreements_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Carrying amount of securities secured</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue" xlink:label="us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue" xlink:to="us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pledged Assets Separately Reported, Securities Pledged for Repurchase Agreements, at Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PledgedAssetsSeparatelyReportedSecuritiesPledgedForRepurchaseAgreementsAtFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair value of the pledged collateral</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity" xlink:label="osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity" xlink:to="osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the number of customers having secured balances exceeding specified percentage of stockholders equity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of Customers Having Secured Balances Exceeding Specified Percentage of Stockholders Equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of customers having secured balances exceeding specified percentage of stockholders equity</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ThresholdForDisclosurePercentageOfStockholdersEquity" xlink:label="osbc_ThresholdForDisclosurePercentageOfStockholdersEquity" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ThresholdForDisclosurePercentageOfStockholdersEquity" xlink:to="osbc_ThresholdForDisclosurePercentageOfStockholdersEquity_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ThresholdForDisclosurePercentageOfStockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the threshold percentage which the entity uses for disclosure about the customer holding secured balances.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ThresholdForDisclosurePercentageOfStockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Threshold for Disclosure Percentage of Stockholders Equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ThresholdForDisclosurePercentageOfStockholdersEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Threshold percentage of stockholders' equity</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets" xlink:label="osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets" xlink:to="osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of borrowings from Federal Home Loan Bank as a percentage of total assets.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank, Advances as Percentage of Total Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Borrowings at FHLBC as percentage of total assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:to="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument, Interest Rate, Stated Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DebtInstrumentInterestRateStatedPercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest rate (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch" xlink:label="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch" xlink:to="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank, Advances, Branch of FHLB Bank, Amount of Advances</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FederalHomeLoanBankAdvancesBranchOfFHLBBankAmountOfAdvancesByBranch_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FHLBC advance amount</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue" xlink:label="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue" xlink:to="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the fair value of securities pledged as collateral in support of federal home loan bank advances outstanding</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Advances General Debt Obligations Disclosures Collateral Pledged Securities Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair value of securities collateralized</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations" xlink:label="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations" xlink:to="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the principal balance of loans pledged as collateral in support of federal home loan bank advances outstanding.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Advances General Debt Obligations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Principal balance of loans collateralized</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:to="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Line of Credit Facility, Maximum Borrowing Capacity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Maximum borrowing capacity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount" xlink:label="us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount" xlink:to="us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument, Unused Borrowing Capacity, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentUnusedBorrowingCapacityAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount available for additional borrowings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentTerm" xlink:label="us-gaap_DebtInstrumentTerm" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentTerm" xlink:to="us-gaap_DebtInstrumentTerm_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument, Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Warrant term</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DebtInstrumentInterestRateTerm" xlink:label="osbc_DebtInstrumentInterestRateTerm" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DebtInstrumentInterestRateTerm" xlink:to="osbc_DebtInstrumentInterestRateTerm_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DebtInstrumentInterestRateTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the period for which the interest rate is applicable.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DebtInstrumentInterestRateTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument Interest Rate Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DebtInstrumentInterestRateTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest rate term</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1" xlink:to="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument, Basis Spread on Variable Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Basis points added to reference rate (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredFinanceCostsNet" xlink:label="us-gaap_DeferredFinanceCostsNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredFinanceCostsNet" xlink:to="us-gaap_DeferredFinanceCostsNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredFinanceCostsNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Issuance Costs, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredFinanceCostsNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt issuance costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_DeferredFinanceCostsNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Junior Subordinated Debentures issuance cost</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TermOfDeferredFinancingCosts" xlink:label="osbc_TermOfDeferredFinancingCosts" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TermOfDeferredFinancingCosts" xlink:to="osbc_TermOfDeferredFinancingCosts_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TermOfDeferredFinancingCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization period for deferred financing costs.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TermOfDeferredFinancingCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Term of Deferred Financing Costs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TermOfDeferredFinancingCosts_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization period for deferred financing costs</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtByMaturityAbstract" xlink:label="us-gaap_LongTermDebtByMaturityAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermDebtByMaturityAbstract" xlink:to="us-gaap_LongTermDebtByMaturityAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermDebtByMaturityAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long-term Debt, Fiscal Year Maturity [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermDebtByMaturityAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Scheduled maturities and weighted average rates of borrowings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths" xlink:to="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInNextTwelveMonths_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Year one</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo" xlink:to="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long-term Debt, Maturities, Repayments of Principal in Year Two</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalInYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Year two</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive" xlink:to="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long-term Debt, Maturities, Repayments of Principal after Year Five</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongTermDebtMaturitiesRepaymentsOfPrincipalAfterYearFive_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Thereafter</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_LongTermDebtByMaturityWeightedAverageInterestRateAbstract" xlink:label="osbc_LongTermDebtByMaturityWeightedAverageInterestRateAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_LongTermDebtByMaturityWeightedAverageInterestRateAbstract" xlink:to="osbc_LongTermDebtByMaturityWeightedAverageInterestRateAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LongTermDebtByMaturityWeightedAverageInterestRateAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long Term Debt by Maturity Weighted Average Interest Rate [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_LongTermDebtByMaturityWeightedAverageInterestRateAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Weighted Average Rate</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths" xlink:label="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths" xlink:to="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The weighted average interest rate applicable to debt (including short-term and current portion of long term debt) maturing within the next twelve months following the date of the latest balance sheet presented in the financial statements.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Maturities Repayments of Principal Weighted Average Interest Rate in Next Twelve Months</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Year one (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo" xlink:label="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo" xlink:to="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The weighted average interest rate applicable to long-term debt maturing in year two following the date of the latest balance sheet presented in the financial statements.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long term Debt Maturities Repayments of Principal Weighted Average Interest Rate in Year Two</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Year two (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive" xlink:label="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive" xlink:to="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The weighted average interest rate applicable to long-term debt maturing after year five following the date of the latest balance sheet presented in the financial statements.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long term Debt Maturities Repayments of Principal Weighted Average Interest Rate after Year Five</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Thereafter (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate" xlink:label="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate" xlink:to="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The weighted average interest rate applicable to debt (including short-term and current portion of long term debt).</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Maturities Repayments of Principal Weighted Average Interest Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeAxis" xlink:label="us-gaap_LongtermDebtTypeAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongtermDebtTypeAxis" xlink:to="us-gaap_LongtermDebtTypeAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongtermDebtTypeAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long-term Debt, Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LongtermDebtTypeDomain" xlink:label="us-gaap_LongtermDebtTypeDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LongtermDebtTypeDomain" xlink:to="us-gaap_LongtermDebtTypeDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Longterm Debt Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LongtermDebtTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Long-term Debt, Type [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_JuniorSubordinatedDebtMember" xlink:label="us-gaap_JuniorSubordinatedDebtMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_JuniorSubordinatedDebtMember" xlink:to="us-gaap_JuniorSubordinatedDebtMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_JuniorSubordinatedDebtMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Junior Subordinated Debt [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_JuniorSubordinatedDebtMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Junior subordinated debentures</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesAxis" xlink:label="srt_ConsolidatedEntitiesAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ConsolidatedEntitiesAxis" xlink:to="srt_ConsolidatedEntitiesAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_ConsolidatedEntitiesAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Consolidated Entities [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ConsolidatedEntitiesDomain" xlink:label="srt_ConsolidatedEntitiesDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ConsolidatedEntitiesDomain" xlink:to="srt_ConsolidatedEntitiesDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_ConsolidatedEntitiesDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Consolidated Entities [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_ConsolidatedEntitiesDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Consolidated Entities [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OldSecondCapitalTrustIMember" xlink:label="osbc_OldSecondCapitalTrustIMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OldSecondCapitalTrustIMember" xlink:to="osbc_OldSecondCapitalTrustIMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OldSecondCapitalTrustIMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents Old Second Capital Trust I, an unconsolidated subsidiary of the entity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OldSecondCapitalTrustIMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Old Second Capital Trust I [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OldSecondCapitalTrustIMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Old Second Capital Trust I</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProceedsFromIssuanceOfTrustPreferredSecurities" xlink:label="us-gaap_ProceedsFromIssuanceOfTrustPreferredSecurities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProceedsFromIssuanceOfTrustPreferredSecurities" xlink:to="us-gaap_ProceedsFromIssuanceOfTrustPreferredSecurities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProceedsFromIssuanceOfTrustPreferredSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from Issuance of Trust Preferred Securities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProceedsFromIssuanceOfTrustPreferredSecurities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Proceeds from sale of cumulative trust preferred securities</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TrustPreferredSecuritiesMaturityPeriod" xlink:label="osbc_TrustPreferredSecuritiesMaturityPeriod" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TrustPreferredSecuritiesMaturityPeriod" xlink:to="osbc_TrustPreferredSecuritiesMaturityPeriod_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TrustPreferredSecuritiesMaturityPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the maturity period of trust preferred securities.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TrustPreferredSecuritiesMaturityPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Trust Preferred Securities Maturity Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TrustPreferredSecuritiesMaturityPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Maturity Period</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TrustPreferredSecuritiesCashDistributionRatePercentage" xlink:label="osbc_TrustPreferredSecuritiesCashDistributionRatePercentage" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TrustPreferredSecuritiesCashDistributionRatePercentage" xlink:to="osbc_TrustPreferredSecuritiesCashDistributionRatePercentage_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TrustPreferredSecuritiesCashDistributionRatePercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the annual rate of cash distributions on the securities, which are payable quarterly.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TrustPreferredSecuritiesCashDistributionRatePercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Trust Preferred Securities Cash Distribution Rate Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TrustPreferredSecuritiesCashDistributionRatePercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash distribution rate of trust preferred securities (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TrustPreferredSecuritiesCashDistributionFixedRatePercentage" xlink:label="osbc_TrustPreferredSecuritiesCashDistributionFixedRatePercentage" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TrustPreferredSecuritiesCashDistributionFixedRatePercentage" xlink:to="osbc_TrustPreferredSecuritiesCashDistributionFixedRatePercentage_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TrustPreferredSecuritiesCashDistributionFixedRatePercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the fixed annual rate of cash distributions on the securities.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TrustPreferredSecuritiesCashDistributionFixedRatePercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Trust Preferred Securities, Cash Distribution Fixed Rate Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TrustPreferredSecuritiesCashDistributionFixedRatePercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash distribution fixed rate of trust preferred securities (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TrustPreferredSecuritiesBasisSpreadOnVariableRate" xlink:label="osbc_TrustPreferredSecuritiesBasisSpreadOnVariableRate" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TrustPreferredSecuritiesBasisSpreadOnVariableRate" xlink:to="osbc_TrustPreferredSecuritiesBasisSpreadOnVariableRate_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TrustPreferredSecuritiesBasisSpreadOnVariableRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The percentage points added to the reference rate to compute the variable rate on the trust preferred securities.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TrustPreferredSecuritiesBasisSpreadOnVariableRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Trust Preferred Securities Basis Spread on Variable Rate</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TrustPreferredSecuritiesBasisSpreadOnVariableRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Basis points added to cash distribution floating rate base (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TrustPreferredSecuritiesDescriptionOfVariableRateBasis" xlink:label="osbc_TrustPreferredSecuritiesDescriptionOfVariableRateBasis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TrustPreferredSecuritiesDescriptionOfVariableRateBasis" xlink:to="osbc_TrustPreferredSecuritiesDescriptionOfVariableRateBasis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TrustPreferredSecuritiesDescriptionOfVariableRateBasis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The reference rate for the variable rate of the trust preferred securities, such as LIBOR or the US treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TrustPreferredSecuritiesDescriptionOfVariableRateBasis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Trust Preferred Securities Description of Variable Rate Basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TrustPreferredSecuritiesDescriptionOfVariableRateBasis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash distribution, floating rate base</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TrustPreferredSecuritiesIssuanceCostAmortizationPeriod" xlink:label="osbc_TrustPreferredSecuritiesIssuanceCostAmortizationPeriod" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TrustPreferredSecuritiesIssuanceCostAmortizationPeriod" xlink:to="osbc_TrustPreferredSecuritiesIssuanceCostAmortizationPeriod_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TrustPreferredSecuritiesIssuanceCostAmortizationPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amortization period of the costs associated with the issuance of the trust preferred securities.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TrustPreferredSecuritiesIssuanceCostAmortizationPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Trust Preferred Securities Issuance Cost Amortization Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TrustPreferredSecuritiesIssuanceCostAmortizationPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization period</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_InterestPaymentDefermentPeriod" xlink:label="osbc_InterestPaymentDefermentPeriod" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_InterestPaymentDefermentPeriod" xlink:to="osbc_InterestPaymentDefermentPeriod_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_InterestPaymentDefermentPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The period up to which the interest payments may be deferred.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_InterestPaymentDefermentPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Payment Deferment Period</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:label="us-gaap_ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:to="us-gaap_ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Components of Income Tax Expense (Benefit), Continuing Operations [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ComponentsOfIncomeTaxExpenseBenefitContinuingOperationsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Components of income tax expense (benefit)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CurrentFederalTaxExpenseBenefit" xlink:label="us-gaap_CurrentFederalTaxExpenseBenefit" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CurrentFederalTaxExpenseBenefit" xlink:to="us-gaap_CurrentFederalTaxExpenseBenefit_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CurrentFederalTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Current Federal Tax Expense (Benefit)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CurrentFederalTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Current federal</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CurrentStateAndLocalTaxExpenseBenefit" xlink:to="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Current State and Local Tax Expense (Benefit)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CurrentStateAndLocalTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Current state</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xlink:label="us-gaap_DeferredFederalIncomeTaxExpenseBenefit" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilitiesMortgageServicingRights" xlink:to="us-gaap_DeferredTaxLiabilitiesMortgageServicingRights_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredTaxLiabilitiesMortgageServicingRights_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Liabilities, Mortgage Servicing Rights</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_DeferredTaxLiabilitiesMortgageServicingRights_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage servicing rights</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredTaxLiabilitiesIntangibleAssetsAmortization" xlink:label="osbc_DeferredTaxLiabilitiesIntangibleAssetsAmortization" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredTaxLiabilitiesIntangibleAssetsAmortization" xlink:to="osbc_DeferredTaxLiabilitiesIntangibleAssetsAmortization_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredTaxLiabilitiesIntangibleAssetsAmortization_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of deferred tax liability attributable to taxable temporary differences from amortization of intangible assets.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredTaxLiabilitiesIntangibleAssetsAmortization_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Liabilities, Intangible Assets, Amortization</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_DeferredTaxLiabilitiesIntangibleAssetsAmortization_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of core deposit intangible</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredTaxLiabilitiesStateTaxBenefits" xlink:label="osbc_DeferredTaxLiabilitiesStateTaxBenefits" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredTaxLiabilitiesStateTaxBenefits" xlink:to="osbc_DeferredTaxLiabilitiesStateTaxBenefits_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredTaxLiabilitiesStateTaxBenefits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of deferred tax liability attributable to taxable temporary differences from state tax benefits.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredTaxLiabilitiesStateTaxBenefits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Liabilities State Tax Benefits</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_DeferredTaxLiabilitiesStateTaxBenefits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">State tax benefits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredTaxLiabilitiesOther" xlink:label="us-gaap_DeferredTaxLiabilitiesOther" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxLiabilitiesOther" xlink:to="us-gaap_DeferredTaxLiabilitiesOther_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredTaxLiabilitiesOther_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Liabilities, Other</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_DeferredTaxLiabilitiesOther_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other liabilities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredIncomeTaxLiabilities" xlink:label="us-gaap_DeferredIncomeTaxLiabilities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxLiabilities" xlink:to="us-gaap_DeferredIncomeTaxLiabilities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredIncomeTaxLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Liabilities, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:label="us-gaap_DeferredIncomeTaxLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total deferred tax liabilities</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredTaxAssetsLiabilitiesGross" xlink:label="osbc_DeferredTaxAssetsLiabilitiesGross" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredTaxAssetsLiabilitiesGross" xlink:to="osbc_DeferredTaxAssetsLiabilitiesGross_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredTaxAssetsLiabilitiesGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount before allocation of valuation allowances of deferred tax asset and liability attributable to deductible temporary differences and carryforwards.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredTaxAssetsLiabilitiesGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Assets Liabilities Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="osbc_DeferredTaxAssetsLiabilitiesGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net deferred tax asset before valuation allowance</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss" xlink:label="osbc_TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss" xlink:to="osbc_TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the tax effect of adjustments related to other comprehensive loss.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Effect Of Adjustments Related To Other Comprehensive Loss</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax effect of adjustments related to other comprehensive loss</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredTaxAssetsLiabilitiesNet" xlink:to="us-gaap_DeferredTaxAssetsLiabilitiesNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Assets, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_DeferredTaxAssetsLiabilitiesNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net deferred tax asset</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:to="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Corporate federal tax rate</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLossCarryforwardsTable" xlink:label="us-gaap_OperatingLossCarryforwardsTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLossCarryforwardsTable" xlink:to="us-gaap_OperatingLossCarryforwardsTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLossCarryforwardsTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Loss Carryforwards [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxAuthorityAxis" xlink:label="us-gaap_IncomeTaxAuthorityAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxAuthorityAxis" xlink:to="us-gaap_IncomeTaxAuthorityAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxAuthorityAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Tax Authority [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxAuthorityDomain" xlink:label="us-gaap_IncomeTaxAuthorityDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxAuthorityDomain" xlink:to="us-gaap_IncomeTaxAuthorityDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxAuthorityDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Tax Authority [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxAuthorityDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Tax Authority [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DomesticCountryMember" xlink:label="us-gaap_DomesticCountryMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DomesticCountryMember" xlink:to="us-gaap_DomesticCountryMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DomesticCountryMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Domestic Country [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DomesticCountryMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StateAndLocalJurisdictionMember" xlink:label="us-gaap_StateAndLocalJurisdictionMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StateAndLocalJurisdictionMember" xlink:to="us-gaap_StateAndLocalJurisdictionMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">State And Local Jurisdiction [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StateAndLocalJurisdictionMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">State</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TaxPeriodAxis" xlink:label="us-gaap_TaxPeriodAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxPeriodAxis" xlink:to="us-gaap_TaxPeriodAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxPeriodAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Period [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TaxPeriodDomain" xlink:label="us-gaap_TaxPeriodDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxPeriodDomain" xlink:to="us-gaap_TaxPeriodDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxPeriodDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Period [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TaxPeriodDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Period [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ExpirationYear2025Member" xlink:label="osbc_ExpirationYear2025Member" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ExpirationYear2025Member" xlink:to="osbc_ExpirationYear2025Member_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ExpirationYear2025Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the expiration year 2025 for operating loss carryforwards.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ExpirationYear2025Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Expiration Year2025 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ExpirationYear2025Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2025</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TaxCreditCarryforwardAxis" xlink:label="us-gaap_TaxCreditCarryforwardAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxCreditCarryforwardAxis" xlink:to="us-gaap_TaxCreditCarryforwardAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxCreditCarryforwardAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Credit Carryforward [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TaxCreditCarryforwardNameDomain" xlink:label="us-gaap_TaxCreditCarryforwardNameDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxCreditCarryforwardNameDomain" xlink:to="us-gaap_TaxCreditCarryforwardNameDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxCreditCarryforwardNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Credit Carryforward Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TaxCreditCarryforwardNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Credit Carryforward, Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AlternativeMinimumMember" xlink:label="osbc_AlternativeMinimumMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AlternativeMinimumMember" xlink:to="osbc_AlternativeMinimumMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AlternativeMinimumMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax credit carryforwards arising from alternative minimum taxes.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AlternativeMinimumMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Alternative Minimum [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AlternativeMinimumMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Alternative minimum tax credit</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLossCarryforwardsLineItems" xlink:label="us-gaap_OperatingLossCarryforwardsLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLossCarryforwardsLineItems" xlink:to="us-gaap_OperatingLossCarryforwardsLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLossCarryforwardsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Loss Carryforwards [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLossCarryforwardsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net operating loss carryforward</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLossCarryforwards" xlink:label="us-gaap_OperatingLossCarryforwards" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLossCarryforwards" xlink:to="us-gaap_OperatingLossCarryforwards_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLossCarryforwards_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Loss Carryforwards</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLossCarryforwards_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net operating loss carryforward</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TaxCreditCarryforwardAmount" xlink:label="us-gaap_TaxCreditCarryforwardAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TaxCreditCarryforwardAmount" xlink:to="us-gaap_TaxCreditCarryforwardAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TaxCreditCarryforwardAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax Credit Carryforward, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TaxCreditCarryforwardAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Alternative minimum tax credit that can be carried forward</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ComponentsOfDeferredIncomeTaxExpenseBenefitAbstract" xlink:label="osbc_ComponentsOfDeferredIncomeTaxExpenseBenefitAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ComponentsOfDeferredIncomeTaxExpenseBenefitAbstract" xlink:to="osbc_ComponentsOfDeferredIncomeTaxExpenseBenefitAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ComponentsOfDeferredIncomeTaxExpenseBenefitAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Components of Deferred Income Tax Expense (Benefit) [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ComponentsOfDeferredIncomeTaxExpenseBenefitAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Components of the provision for deferred income taxes</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to provision for loan losses.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Provision for Loan Losses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision for loan losses</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitDeferredCompensation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitDeferredCompensation" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitDeferredCompensation" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitDeferredCompensation_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitDeferredCompensation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to deferred compensation.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitDeferredCompensation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Deferred Compensation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitDeferredCompensation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred compensation</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to intangible assets other than goodwill.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Goodwill and Intangible Assets Intangible Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amortization of core deposit intangible</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to share based compensation.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Share Based Compensation Cost</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stock option compensation</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to business combination adjustments.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit), Business Combination Adjustments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Business combination adjustments</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to wrote downs on other real estate owned.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Other Real Estate Owned Write Downs</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">OREO write downs</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to deductible domestic operating loss carryforwards, excluding state and local operating loss carryforwards.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Operating Loss Carryforwards Domestic</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal net operating loss carryforward</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to deductible state and local operating loss carryforwards.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Operating Loss Carryforwards State and Local</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">State net operating loss carryforward</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredTaxAssetsTaxCredit" xlink:label="osbc_DeferredTaxAssetsTaxCredit" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredTaxAssetsTaxCredit" xlink:to="osbc_DeferredTaxAssetsTaxCredit_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredTaxAssetsTaxCredit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of deferred income tax expense (benefit) for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to deferred tax credits.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredTaxAssetsTaxCredit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Tax Assets, Tax Credit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_DeferredTaxAssetsTaxCredit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred tax credit</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitDepreciation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitDepreciation" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitDepreciation" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitDepreciation_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitDepreciation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to depreciation.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitDepreciation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Depreciation</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitDepreciation_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Depreciation</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitMortgageServicingRights" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitMortgageServicingRights" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitMortgageServicingRights" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitMortgageServicingRights_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitMortgageServicingRights_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to mortgage servicing rights.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitMortgageServicingRights_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Mortgage Servicing Rights</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitMortgageServicingRights_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage servicing rights</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to goodwill.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Goodwill and Intangible Assets Goodwill</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Goodwill amortization/impairment</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DeferredIncomeTaxExpenseBenefitStateTaxBenefits" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitStateTaxBenefits" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitStateTaxBenefits" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitStateTaxBenefits_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitStateTaxBenefits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) pertaining to state tax benefits.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitStateTaxBenefits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) State Tax Benefits</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitStateTaxBenefits_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">State tax benefits</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DeferredIncomeTaxExpenseBenefitOther" xlink:to="osbc_DeferredIncomeTaxExpenseBenefitOther_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOther_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The component of income tax expense for the period representing the increase (decrease) in the entity's deferred income tax expense (benefit) not separately disclosed.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOther_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit) Other</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DeferredIncomeTaxExpenseBenefitOther_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredIncomeTaxExpenseBenefit" xlink:to="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Income Tax Expense (Benefit)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Provision for deferred tax expense (benefit)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_DeferredIncomeTaxExpenseBenefit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total deferred tax benefit</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:label="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract" xlink:to="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Effective Income Tax Rate Reconciliation, Amount [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxExpenseBenefitContinuingOperationsIncomeTaxReconciliationAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Difference between effective tax rates and federal statutory rates applied to financial statement income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate" xlink:to="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxReconciliationIncomeTaxExpenseBenefitAtFederalStatutoryIncomeTaxRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tax at statutory federal income tax rate</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:label="us-gaap_IncomeTaxReconciliationTaxExemptIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationTaxExemptIncome" xlink:to="us-gaap_IncomeTaxReconciliationTaxExemptIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxReconciliationTaxExemptIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_IncomeTaxReconciliationTaxExemptIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Nontaxable interest income, net of disallowed interest deduction</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome" xlink:label="osbc_IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome" xlink:to="osbc_IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of income tax reconciliation non-deductible bank owned life insurance income.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Tax Reconciliation Non Deductible Bank Owned Life Insurance Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="osbc_IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">BOLI Income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes" xlink:to="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxReconciliationStateAndLocalIncomeTaxes_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">State income taxes, net of federal benefit</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost" xlink:to="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Effective Income Tax Rate Reconciliation, Nondeductible Expense, Share-based Compensation Cost, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_IncomeTaxReconciliationNondeductibleExpenseShareBasedCompensationCost_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stock based compensation</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate" xlink:label="us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate" xlink:to="us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxReconciliationChangeInEnactedTaxRate_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impact of Illinois tax rate change</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:label="us-gaap_IncomeTaxReconciliationOtherAdjustments" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeTaxReconciliationOtherAdjustments" xlink:to="us-gaap_IncomeTaxReconciliationOtherAdjustments_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeTaxReconciliationOtherAdjustments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Effective Income Tax Rate Reconciliation, Other Adjustments, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeTaxReconciliationOtherAdjustments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AwardTypeAxis" xlink:label="us-gaap_AwardTypeAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AwardTypeAxis" xlink:to="us-gaap_AwardTypeAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AwardTypeAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Award Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share Based Compensation Arrangements By Share Based Payment Award Award Type And Plan Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Award [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_EmployeeAndNonemployeeStockOptionsMember" xlink:label="osbc_EmployeeAndNonemployeeStockOptionsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_EmployeeAndNonemployeeStockOptionsMember" xlink:to="osbc_EmployeeAndNonemployeeStockOptionsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_EmployeeAndNonemployeeStockOptionsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">An arrangement whereby an employee and nonemployee is entitled to receive in the future, subject to vesting and other restrictions, a number of shares in the entity at a specified price, as defined in the agreement. Although there are variations, normally, after vesting, when an option is exercised, the holder pays the strike value in cash to the entity and receives equity shares. The equity shares can be sold into the market for cash at the current market price without restriction.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_EmployeeAndNonemployeeStockOptionsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Employee And Nonemployee Stock Options [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_EmployeeAndNonemployeeStockOptionsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stock options</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameAxis" xlink:label="us-gaap_PlanNameAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameAxis" xlink:to="us-gaap_PlanNameAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PlanNameAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Plan Name [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PlanNameDomain" xlink:label="us-gaap_PlanNameDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PlanNameDomain" xlink:to="us-gaap_PlanNameDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PlanNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Plan Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PlanNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Plan Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_EquityIncentivePlan2014Member" xlink:label="osbc_EquityIncentivePlan2014Member" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_EquityIncentivePlan2014Member" xlink:to="osbc_EquityIncentivePlan2014Member_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_EquityIncentivePlan2014Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents activity related to the 2014 Equity Incentive Plan (the "2014 Plan").</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_EquityIncentivePlan2014Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity Incentive Plan2014 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_EquityIncentivePlan2014Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2014 Plan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of shares authorized</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Granted (in shares)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationTerm" xlink:label="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationTerm" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share Based Compensation Arrangement by Share Based Payment Award, Expiration Term</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Vesting period</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Exercised (in shares)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Stock Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedStockOptions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total unrecognized compensation cost</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Shares</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending outstanding (in shares)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Beginning outstanding (in shares)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Exercisable at end of period (in shares)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePriceRollforward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Weighted Average Exercise Price</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending outstanding (in dollars per share)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingWeightedAverageExercisePrice_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Beginning outstanding (in dollars per share)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Exercised (in dollars per share)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:to="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Exercisable at end of period (in dollars per share)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:label="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" xlink:to="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share Based Compensation Arrangement by Share Based Payment Award, Options, Weighted Average Remaining Contractual Term [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Weighted Average Remaining Contractual Term (years)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending outstanding (in years)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsExercisableWeightedAverageRemainingContractualTerm1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Exercisable at end of period</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract" xlink:label="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract" xlink:to="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Aggregate Intrinsic Value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Exercised (in dollars)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Intrinsic value of options exercised</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of shares issuable</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RestrictedStockAndRestrictedStockUnitsMember" xlink:label="osbc_RestrictedStockAndRestrictedStockUnitsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RestrictedStockAndRestrictedStockUnitsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Restricted Stock And Restricted Stock Units [Member]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Changes in unvested awards</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Nonvested at the end of the period (in shares)</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Nonvested at the beginning of the period (in shares)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Granted (in shares)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Vested (in shares)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Weighted Average Grant Date Fair Value</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Nonvested at the end of the period (in dollars per share)</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:label="us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Employee Service Share-based Compensation, Nonvested Awards, Compensation Not yet Recognized, Share-based Awards Other than Options</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedShareBasedAwardsOtherThanOptions_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total unrecognized compensation cost of restricted awards</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1" xlink:to="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Expected weighted-average period for recognition of unrecognized compensation</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ScheduleOfEarningsPerShareBasicAndDilutedTable" xlink:label="osbc_ScheduleOfEarningsPerShareBasicAndDilutedTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ScheduleOfEarningsPerShareBasicAndDilutedTable" xlink:to="osbc_ScheduleOfEarningsPerShareBasicAndDilutedTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ScheduleOfEarningsPerShareBasicAndDilutedTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Disclosure pertaining to the entity's basic and diluted earnings per share.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ScheduleOfEarningsPerShareBasicAndDilutedTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Earnings Per Share Basic and Diluted [Table]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_EarningsPerShareBasicAndDilutedLineItems" xlink:label="osbc_EarningsPerShareBasicAndDilutedLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_EarningsPerShareBasicAndDilutedLineItems" xlink:to="osbc_EarningsPerShareBasicAndDilutedLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_EarningsPerShareBasicAndDilutedLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Earnings Per Share Basic and Diluted [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_EarningsPerShareBasicAndDilutedLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Earnings Per Share</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerShareBasicAbstract" xlink:label="us-gaap_EarningsPerShareBasicAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareBasicAbstract" xlink:to="us-gaap_EarningsPerShareBasicAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerShareBasicAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Earnings Per Share, Basic [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EarningsPerShareBasicAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Basic earnings per share:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:to="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Weighted Average Number of Shares Outstanding, Basic</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Weighted-average common shares outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EarningsPerShareDilutedAbstract" xlink:label="us-gaap_EarningsPerShareDilutedAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EarningsPerShareDilutedAbstract" xlink:to="us-gaap_EarningsPerShareDilutedAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EarningsPerShareDilutedAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Earnings Per Share, Diluted [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EarningsPerShareDilutedAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Diluted earnings per share:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:to="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dilutive effect of share-based payment awards (in shares)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:to="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Weighted Average Number of Shares Outstanding, Diluted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Diluted average common shares outstanding</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted" xlink:to="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net Income (Loss) Available to Common Stockholders, Diluted</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net earnings available to common stockholders</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Antidilutive securities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable" xlink:to="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfFairValueOffBalanceSheetRisksTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Fair Value, Off-balance Sheet Risks [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditFacilityAxis" xlink:label="us-gaap_CreditFacilityAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CreditFacilityAxis" xlink:to="us-gaap_CreditFacilityAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CreditFacilityAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Credit Facility [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditFacilityDomain" xlink:label="us-gaap_CreditFacilityDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CreditFacilityDomain" xlink:to="us-gaap_CreditFacilityDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CreditFacilityDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Credit Facility [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CreditFacilityDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Credit Facility [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FixedLettersOfCreditMember" xlink:label="osbc_FixedLettersOfCreditMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FixedLettersOfCreditMember" xlink:to="osbc_FixedLettersOfCreditMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FixedLettersOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the fixed portion of the letter of credit.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FixedLettersOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fixed Letters Of Credit [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FixedLettersOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fixed</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_VariableLettersOfCreditMember" xlink:label="osbc_VariableLettersOfCreditMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_VariableLettersOfCreditMember" xlink:to="osbc_VariableLettersOfCreditMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_VariableLettersOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the variable portion of the letter of credit.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_VariableLettersOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Variable Letters Of Credit [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_VariableLettersOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Variable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LetterOfCreditMember" xlink:label="us-gaap_LetterOfCreditMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LetterOfCreditMember" xlink:to="us-gaap_LetterOfCreditMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LetterOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Letter Of Credit [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LetterOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total.</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CommitmentsToExtendCreditMember" xlink:label="us-gaap_CommitmentsToExtendCreditMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CommitmentsToExtendCreditMember" xlink:to="us-gaap_CommitmentsToExtendCreditMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CommitmentsToExtendCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commitments To Extend Credit [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CommitmentsToExtendCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commitments to Extend Credit [Member]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommitmentsToExtendCreditToBorrowersMember" xlink:label="osbc_CommitmentsToExtendCreditToBorrowersMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommitmentsToExtendCreditToBorrowersMember" xlink:to="osbc_CommitmentsToExtendCreditToBorrowersMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommitmentsToExtendCreditToBorrowersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the loan commitments to borrowers that are legally binding commitments to extend credit to counterparty under certain terms and conditions.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommitmentsToExtendCreditToBorrowersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commitments To Extend Credit To Borrowers [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommitmentsToExtendCreditToBorrowersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Borrower</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommitmentsToExtendCreditNonborrowersMember" xlink:label="osbc_CommitmentsToExtendCreditNonborrowersMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommitmentsToExtendCreditNonborrowersMember" xlink:to="osbc_CommitmentsToExtendCreditNonborrowersMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommitmentsToExtendCreditNonborrowersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the loan commitments on behalf of non-borrowers that are legally binding commitments to extend credit to counterparty under certain terms and conditions.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommitmentsToExtendCreditNonborrowersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commitments To Extend Credit Nonborrowers [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommitmentsToExtendCreditNonborrowersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Nonborrower</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_UnusedLinesOfCreditMember" xlink:label="us-gaap_UnusedLinesOfCreditMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_UnusedLinesOfCreditMember" xlink:to="us-gaap_UnusedLinesOfCreditMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_UnusedLinesOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Unused Lines Of Credit [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_UnusedLinesOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Unused lines of Credit</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingenciesByNatureOfContingencyAxis" xlink:to="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LossContingenciesByNatureOfContingencyAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loss Contingency Nature [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LossContingencyNatureDomain" xlink:label="us-gaap_LossContingencyNatureDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LossContingencyNatureDomain" xlink:to="us-gaap_LossContingencyNatureDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loss Contingency Nature [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LossContingencyNatureDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loss Contingency, Nature [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialStandbyLetterOfCreditMember" xlink:label="us-gaap_FinancialStandbyLetterOfCreditMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancialStandbyLetterOfCreditMember" xlink:to="us-gaap_FinancialStandbyLetterOfCreditMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancialStandbyLetterOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial Standby Letter Of Credit [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancialStandbyLetterOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial standby</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StandbyLettersOfCreditMember" xlink:label="us-gaap_StandbyLettersOfCreditMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StandbyLettersOfCreditMember" xlink:to="us-gaap_StandbyLettersOfCreditMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StandbyLettersOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Standby Letters Of Credit [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StandbyLettersOfCreditMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial standby</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PerformanceGuaranteeMember" xlink:label="us-gaap_PerformanceGuaranteeMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PerformanceGuaranteeMember" xlink:to="us-gaap_PerformanceGuaranteeMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PerformanceGuaranteeMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Performance Guarantee [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PerformanceGuaranteeMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Performance standby</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems" xlink:label="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems" xlink:to="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, Off-balance Sheet Risks, Disclosure Information [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueOffBalanceSheetRisksDisclosureInformationLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial instrument commitments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability" xlink:to="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Disclosure, Off-balance Sheet Risks, Amount, Liability</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksAmountLiability_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial instrument commitments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability" xlink:to="us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Disclosure, Off-balance Sheet Risks, Face Amount, Liability</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueDisclosureOffbalanceSheetRisksFaceAmountLiability_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loan commitments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Estimated aggregate minimum annual rental commitments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases, Future Minimum Payments Due, Next Twelve Months</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueCurrent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2019</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases, Future Minimum Payments, Due in Two Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInTwoYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2020</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases, Future Minimum Payments, Due in Three Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInThreeYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2021</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases, Future Minimum Payments, Due in Four Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFourYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2022</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases, Future Minimum Payments, Due in Five Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueInFiveYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2023</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OperatingLeasesFutureMinimumPaymentsDueInSixYears" xlink:label="osbc_OperatingLeasesFutureMinimumPaymentsDueInSixYears" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OperatingLeasesFutureMinimumPaymentsDueInSixYears" xlink:to="osbc_OperatingLeasesFutureMinimumPaymentsDueInSixYears_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OperatingLeasesFutureMinimumPaymentsDueInSixYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of required minimum rental payments for operating leases having an initial or remaining non-cancelable lease term in excess of one year due in the sixth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OperatingLeasesFutureMinimumPaymentsDueInSixYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases Future Minimum Payments Due In Six Years</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OperatingLeasesFutureMinimumPaymentsDueInSixYears_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2024</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals" xlink:to="us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases, Future Minimum Payments Due, Future Minimum Sublease Rentals</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingLeasesFutureMinimumPaymentsDueFutureMinimumSubleaseRentals_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Aggregate future minimum rental income receivable under noncancelable leases</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OperatingLeasesLeaseRevenueExpenseNet" xlink:label="osbc_OperatingLeasesLeaseRevenueExpenseNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OperatingLeasesLeaseRevenueExpenseNet" xlink:to="osbc_OperatingLeasesLeaseRevenueExpenseNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OperatingLeasesLeaseRevenueExpenseNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The total amount of net revenue (expense) recognized for the period from operating leases, including minimum lease revenue (expense), contingent revenue (expense), percentage revenue (expense) and sublease revenue (expense).</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OperatingLeasesLeaseRevenueExpenseNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases Lease Revenue (Expense), Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OperatingLeasesLeaseRevenueExpenseNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total facility net operating lease revenue/expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LeaseAndRentalExpense" xlink:label="us-gaap_LeaseAndRentalExpense" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeaseAndRentalExpense" xlink:to="us-gaap_LeaseAndRentalExpense_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LeaseAndRentalExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Leases, Rent Expense</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LeaseAndRentalExpense_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total ATM lease expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable" xlink:label="us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable" xlink:to="us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScheduleOfComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of Compliance with Regulatory Capital Requirements under Banking Regulations [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems" xlink:label="us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems" xlink:to="us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Compliance with Regulatory Capital Requirements under Banking Regulations [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ComplianceWithRegulatoryCapitalRequirementsUnderBankingRegulationsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Regulatory &amp; Capital Matters</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalToAverageAssets" xlink:label="us-gaap_TierOneLeverageCapitalToAverageAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneLeverageCapitalToAverageAssets" xlink:to="us-gaap_TierOneLeverageCapitalToAverageAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneLeverageCapitalToAverageAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Leverage Capital to Average Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneLeverageCapitalToAverageAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier 1 capital leverage ratio (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalToRiskWeightedAssets" xlink:label="us-gaap_CapitalToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalToRiskWeightedAssets" xlink:to="us-gaap_CapitalToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CapitalToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital to Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CapitalToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Risk-based capital ratio (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CapitalCommonAbstract" xlink:label="osbc_CapitalCommonAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CapitalCommonAbstract" xlink:to="osbc_CapitalCommonAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CapitalCommonAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">No definition available.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CapitalCommonAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital Common [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CapitalCommonAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Common equity tier 1 capital to risk weighted assets</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneRiskBasedCapitalCommonEquity" xlink:label="osbc_TierOneRiskBasedCapitalCommonEquity" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneRiskBasedCapitalCommonEquity" xlink:to="osbc_TierOneRiskBasedCapitalCommonEquity_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneRiskBasedCapitalCommonEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier 1 Risk Based Capital, as defined in the regulations, attributable to common shares.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneRiskBasedCapitalCommonEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital, Common Equity</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneRiskBasedCapitalCommonEquity_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Actual</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy" xlink:to="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The minimum amount of Tier 1 Risk Based Common Capital required for capital adequacy purposes under the regulatory framework for prompt corrective action.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Common Capital Required for Capital Adequacy</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized" xlink:to="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The amount of Tier 1 Risk Based Common Capital required to be categorized as well capitalized under the regulatory framework for prompt corrective action.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Common Capital Required to be Well Capitalized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required to Be Well Capitalized</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommonCapitalToRiskBasedRatiosAbstract" xlink:label="osbc_CommonCapitalToRiskBasedRatiosAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommonCapitalToRiskBasedRatiosAbstract" xlink:to="osbc_CommonCapitalToRiskBasedRatiosAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommonCapitalToRiskBasedRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">No definition available.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommonCapitalToRiskBasedRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Common Capital To Risk Based Ratios [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommonCapitalToRiskBasedRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Common equity tier 1 capital to risk weighted assets, Ratio</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets" xlink:label="osbc_TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets" xlink:to="osbc_TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier 1 capital attributable to common equity divided by risk weighted assets as defined by regulations.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital Common Equity To Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Actual (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xlink:to="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The minimum Tier One Common Capital Ratio (Tier one common capital divided by risk-weighted assets) required for capital adequacy purposes under the regulatory framework for prompt corrective action.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Common Capital Required for Capital Adequacy to Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xlink:to="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The Tier 1 common capital ratio (Tier 1 common capital divided by risk weighted assets) required to be categorized as "well capitalized" under the regulatory framework for prompt corrective action.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Common Capital Required to be Well Capitalized to Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required to Be Well Capitalized (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalAbstract" xlink:label="us-gaap_CapitalAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalAbstract" xlink:to="us-gaap_CapitalAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CapitalAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CapitalAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total capital to risk weighted assets, Amount</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_Capital" xlink:label="us-gaap_Capital" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_Capital" xlink:to="us-gaap_Capital_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_Capital_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_Capital_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Actual at period end</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalRequiredForCapitalAdequacy" xlink:label="us-gaap_CapitalRequiredForCapitalAdequacy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalRequiredForCapitalAdequacy" xlink:to="us-gaap_CapitalRequiredForCapitalAdequacy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital Required for Capital Adequacy</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalRequiredToBeWellCapitalized" xlink:label="us-gaap_CapitalRequiredToBeWellCapitalized" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalRequiredToBeWellCapitalized" xlink:to="us-gaap_CapitalRequiredToBeWellCapitalized_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital Required to be Well Capitalized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required to Be Well Capitalized</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CapitalToRiskBasedRatiosAbstract" xlink:label="osbc_CapitalToRiskBasedRatiosAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CapitalToRiskBasedRatiosAbstract" xlink:to="osbc_CapitalToRiskBasedRatiosAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CapitalToRiskBasedRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital to Risk Based Ratios [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CapitalToRiskBasedRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total capital to risk weighted assets, Ratio</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xlink:label="us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xlink:to="us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital Required for Capital Adequacy to Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xlink:label="us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xlink:to="us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Capital Required to be Well Capitalized to Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required to Be Well Capitalized (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalAbstract" xlink:label="us-gaap_TierOneRiskBasedCapitalAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneRiskBasedCapitalAbstract" xlink:to="us-gaap_TierOneRiskBasedCapitalAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneRiskBasedCapitalAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneRiskBasedCapitalAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier 1 capital to risk weighted assets, Amount</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapital" xlink:label="us-gaap_TierOneRiskBasedCapital" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneRiskBasedCapital" xlink:to="us-gaap_TierOneRiskBasedCapital_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneRiskBasedCapital_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneRiskBasedCapital_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Actual</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy" xlink:to="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital Required for Capital Adequacy</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized" xlink:to="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital Required to be Well Capitalized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required to Be Well Capitalized</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RiskBasedRatiosAbstract" xlink:label="us-gaap_RiskBasedRatiosAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RiskBasedRatiosAbstract" xlink:to="us-gaap_RiskBasedRatiosAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RiskBasedRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Risk Based Ratios [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RiskBasedRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier 1 capital to risk weighted assets, Ratio</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets" xlink:label="us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets" xlink:to="us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital to Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneRiskBasedCapitalToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Actual (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" xlink:to="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital Required for Capital Adequacy to Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredForCapitalAdequacyToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" xlink:to="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Risk Based Capital Required to be Well Capitalized to Risk Weighted Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneRiskBasedCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required to Be Well Capitalized (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalAbstract" xlink:label="us-gaap_TierOneLeverageCapitalAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneLeverageCapitalAbstract" xlink:to="us-gaap_TierOneLeverageCapitalAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneLeverageCapitalAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Leverage Capital [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneLeverageCapitalAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier 1 capital to average assets, Amount</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapital" xlink:label="us-gaap_TierOneLeverageCapital" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneLeverageCapital" xlink:to="us-gaap_TierOneLeverageCapital_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneLeverageCapital_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Leverage Capital</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneLeverageCapital_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Actual</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy" xlink:label="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy" xlink:to="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Leverage Capital Required for Capital Adequacy</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacy_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized" xlink:label="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized" xlink:to="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Leverage Capital Required to be Well Capitalized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required to Be Well Capitalized</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LeverageRatiosAbstract" xlink:label="us-gaap_LeverageRatiosAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LeverageRatiosAbstract" xlink:to="us-gaap_LeverageRatiosAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LeverageRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Leverage Ratios [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LeverageRatiosAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier 1 capital to average assets, Ratio</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets" xlink:label="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets" xlink:to="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Leverage Capital Required for Capital Adequacy to Average Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneLeverageCapitalRequiredForCapitalAdequacyToAverageAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required for Capital Adequacy Purposes with Capital Conservation Buffer if applicable (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets" xlink:label="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets" xlink:to="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Leverage Capital Required to be Well Capitalized to Average Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TierOneLeverageCapitalRequiredToBeWellCapitalizedToAverageAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum Required to Be Well Capitalized (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DividendRestrictionsAndDeferralsAbstract" xlink:label="osbc_DividendRestrictionsAndDeferralsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DividendRestrictionsAndDeferralsAbstract" xlink:to="osbc_DividendRestrictionsAndDeferralsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DividendRestrictionsAndDeferralsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividend Restrictions and Deferrals [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DividendRestrictionsAndDeferralsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividend Restrictions and Deferrals</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit" xlink:label="osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit" xlink:to="osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the number of previous years retained profits combined with the current years profits used to determine the amount of dividends that may be paid in any calendar year.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividend Restrictions, Number of Previous Years Retained Profit</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of previous years retained profit considered for dividend payment</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths" xlink:to="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The minimum percentage of Tier 1 Common Capital required to be maintained in the next fiscal year following the latest fiscal year to prevent capital distribution limitations under regulatory capital rules.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Common Equity Capital Distribution Limitation Minimum Regulatory Capital Percentage Next Twelve Months</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum capital requirements, minimum percentage required, 2016</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo" xlink:to="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The minimum percentage of Tier 1 Common Capital required to be maintained in year two following the latest fiscal year to prevent capital distribution limitations under regulatory capital rules.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Common Equity Capital Distribution Limitation Minimum Regulatory Capital Percentage, Year Two</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum capital requirements, minimum percentage required, 2017</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree" xlink:to="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The minimum percentage of Tier 1 Common Capital required to be maintained in year three following the latest fiscal year to prevent capital distribution limitations under regulatory capital rules.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Common Equity Capital Distribution Limitation Minimum Regulatory Capital Percentage, Year Three</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum capital requirements, minimum percentage required, 2018</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter" xlink:to="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The minimum percentage of Tier 1 Common Capital required to be maintained in year four and thereafter following the latest fiscal year to prevent capital distribution limitations under regulatory capital rules.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Tier One Common Equity Capital Distribution Limitation Minimum Regulatory Capital Percentage, Year Four and Thereafter</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Minimum capital requirements, minimum percentage required, 2019 and thereafter</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ForwardContractsMember" xlink:label="us-gaap_ForwardContractsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ForwardContractsMember" xlink:to="us-gaap_ForwardContractsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ForwardContractsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Forward Contracts [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ForwardContractsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Forward MBS contracts and forward loan contracts</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateLockCommitmentsMember" xlink:label="us-gaap_InterestRateLockCommitmentsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestRateLockCommitmentsMember" xlink:to="us-gaap_InterestRateLockCommitmentsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestRateLockCommitmentsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Rate Lock Commitments [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestRateLockCommitmentsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Rate Lock Commitments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_MajorCustomersAxis" xlink:label="srt_MajorCustomersAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_MajorCustomersAxis" xlink:to="srt_MajorCustomersAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_MajorCustomersAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Customer [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_NameOfMajorCustomerDomain" xlink:label="srt_NameOfMajorCustomerDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_NameOfMajorCustomerDomain" xlink:to="srt_NameOfMajorCustomerDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_NameOfMajorCustomerDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Name Of Major Customer [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_NameOfMajorCustomerDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Customer [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalNationalMortgageAssociationMember" xlink:label="osbc_FederalNationalMortgageAssociationMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalNationalMortgageAssociationMember" xlink:to="osbc_FederalNationalMortgageAssociationMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalNationalMortgageAssociationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the Federal National Mortgage Association, an investor of the entity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalNationalMortgageAssociationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal National Mortgage Association [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalNationalMortgageAssociationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal National Mortgage Association</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalHomeLoanMortgageCorporationMember" xlink:label="osbc_FederalHomeLoanMortgageCorporationMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalHomeLoanMortgageCorporationMember" xlink:to="osbc_FederalHomeLoanMortgageCorporationMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalHomeLoanMortgageCorporationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents Federal Home Loan Mortgage Corporation, an investor of the entity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalHomeLoanMortgageCorporationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Mortgage Corporation [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalHomeLoanMortgageCorporationMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Mortgage Corp.</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.sec.gov/invest/2013/invest-2013-01-31.xsd#invest_DerivativeNotionalAmount" xlink:label="invest_DerivativeNotionalAmount" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="invest_DerivativeNotionalAmount" xlink:to="invest_DerivativeNotionalAmount_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="invest_DerivativeNotionalAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivative, Notional Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="invest_DerivativeNotionalAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Notional or Contractual Amount</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="invest_DerivativeNotionalAmount_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Notional Amount</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeFairValueOfDerivativeNet" xlink:label="us-gaap_DerivativeFairValueOfDerivativeNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeFairValueOfDerivativeNet" xlink:to="us-gaap_DerivativeFairValueOfDerivativeNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeFairValueOfDerivativeNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivative, Fair Value, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeFairValueOfDerivativeNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair value</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_AmountOfLoansHeldForSaleSold" xlink:label="osbc_AmountOfLoansHeldForSaleSold" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_AmountOfLoansHeldForSaleSold" xlink:to="osbc_AmountOfLoansHeldForSaleSold_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_AmountOfLoansHeldForSaleSold_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of loans held for sale, sold during the period.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_AmountOfLoansHeldForSaleSold_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of Loans Held for Sale Sold</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_AmountOfLoansHeldForSaleSold_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of loans sold to investors</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Measurements, Recurring and Nonrecurring [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueByMeasurementFrequencyAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Frequency [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementFrequencyDomain" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementFrequencyDomain" xlink:to="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Measurement Frequency [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueMeasurementFrequencyDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, Measurement Frequency [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsRecurringMember" xlink:label="us-gaap_FairValueMeasurementsRecurringMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementsRecurringMember" xlink:to="us-gaap_FairValueMeasurementsRecurringMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Measurements Recurring [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueMeasurementsRecurringMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Recurring</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByFairValueHierarchyLevelAxis" xlink:to="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueByFairValueHierarchyLevelAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, Hierarchy [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementsFairValueHierarchyDomain" xlink:to="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Measurements Fair Value Hierarchy [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueMeasurementsFairValueHierarchyDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Hierarchy [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel1Member" xlink:label="us-gaap_FairValueInputsLevel1Member" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel1Member" xlink:to="us-gaap_FairValueInputsLevel1Member_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Inputs Level1 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueInputsLevel1Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Level 1</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel2Member" xlink:to="us-gaap_FairValueInputsLevel2Member_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Inputs Level2 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueInputsLevel2Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Level 2</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="us-gaap_FairValueInputsLevel3Member" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueInputsLevel3Member" xlink:to="us-gaap_FairValueInputsLevel3Member_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Inputs Level3 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueInputsLevel3Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Level 3</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateSwapMember" xlink:label="us-gaap_InterestRateSwapMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestRateSwapMember" xlink:to="us-gaap_InterestRateSwapMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestRateSwapMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Rate Swap [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestRateSwapMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest rate swap agreements net of swap credit valuation</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:to="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Assets and liabilities measured at fair value on a recurring basis</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Assets and liabilities measured at fair value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases" xlink:to="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Purchases</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="us-gaap_AssetsFairValueDisclosureAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsFairValueDisclosureAbstract" xlink:to="us-gaap_AssetsFairValueDisclosureAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AssetsFairValueDisclosureAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Assets, Fair Value Disclosure [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AssetsFairValueDisclosureAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Assets:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansHeldForSaleFairValueDisclosure" xlink:label="us-gaap_LoansHeldForSaleFairValueDisclosure" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansHeldForSaleFairValueDisclosure" xlink:to="us-gaap_LoansHeldForSaleFairValueDisclosure_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansHeldForSaleFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans Held-for-sale, Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansHeldForSaleFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans held-for-sale</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_LoansHeldForSaleFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans held for sale</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeAssets" xlink:label="us-gaap_DerivativeAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeAssets" xlink:to="us-gaap_DerivativeAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivative Asset</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveTerseLabel" xlink:label="us-gaap_DerivativeAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest rate swap agreements</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="us-gaap_AssetsFairValueDisclosure" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AssetsFairValueDisclosure" xlink:to="us-gaap_AssetsFairValueDisclosure_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AssetsFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Assets, Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_AssetsFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total financial assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_AssetsFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="us-gaap_LiabilitiesFairValueDisclosureAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:to="us-gaap_LiabilitiesFairValueDisclosureAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesFairValueDisclosureAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Liabilities, Fair Value Disclosure [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LiabilitiesFairValueDisclosureAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Liabilities:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeLiabilities" xlink:label="us-gaap_DerivativeLiabilities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeLiabilities" xlink:to="us-gaap_DerivativeLiabilities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivative Liability</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/positiveLabel" xlink:label="us-gaap_DerivativeLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest rate swap</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other liabilities</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="us-gaap_LiabilitiesFairValueDisclosure" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesFairValueDisclosure" xlink:to="us-gaap_LiabilitiesFairValueDisclosure_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial and Nonfinancial Liabilities, Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_LiabilitiesFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:label="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" xlink:to="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Schedule of information required and determined to be provided for purposes of reconciling beginning and ending balances of fair value measurements of assets and liabilities using significant unobservable inputs (level 3). Such reconciliation, separately presenting changes during the period, at a minimum, may include, but is not limited to: (1) total gains or losses for the period (realized and unrealized), segregating those gains or losses included in earnings (or changes in net assets) and gains or losses recognized in other comprehensive income, and a description of where those gains or losses included in earnings (or changes in net assets) are reported in the statement of income (or activities); (2) purchases, sales, issues, and settlements (each type disclosed separately); and (3) transfers in and transfers out of level 3 (for example, transfers due to changes in the observability of significant inputs), by class of asset and liability.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Table]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_MortgageServicingRightsMember" xlink:label="osbc_MortgageServicingRightsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_MortgageServicingRightsMember" xlink:to="osbc_MortgageServicingRightsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_MortgageServicingRightsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the mortgage servicing rights.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_MortgageServicingRightsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Servicing Rights [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_MortgageServicingRightsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage servicing rights</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:label="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" xlink:to="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Assets and liabilities measured at fair value on a recurring basis</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward" xlink:to="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Changes in Level 3</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Ending balance</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:label="us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Beginning balance</label>
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    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses" xlink:label="osbc_ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses" xlink:to="osbc_ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of increase (decrease) in specific allocations within the provision for loan losses for impaired financing receivables.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Impaired Financing Receivable Decrease of Specific Allocations within Provision for Loan Losses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase (decrease) of specific allocations within the provision for loan losses</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RealEstateGross" xlink:label="osbc_RealEstateGross" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_RealEstateGross" xlink:to="osbc_RealEstateGross_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_RealEstateGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the gross carrying amount of real estate owned before the valuation allowance.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RealEstateGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate, Gross</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_RealEstateGross_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Outstanding balance</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RealEstateOwnedParticipations" xlink:label="osbc_RealEstateOwnedParticipations" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_RealEstateOwnedParticipations" xlink:to="osbc_RealEstateOwnedParticipations_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_RealEstateOwnedParticipations_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount of the participations in the real estate owned.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RealEstateOwnedParticipations_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Owned Participations</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_RealEstateOwnedParticipations_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">OREO participations</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="us-gaap_FairValueByBalanceSheetGroupingTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByBalanceSheetGroupingTable" xlink:to="us-gaap_FairValueByBalanceSheetGroupingTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueByBalanceSheetGroupingTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, by Balance Sheet Grouping [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:to="us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Values of Financial Instruments</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract" xlink:to="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial Instruments, Financial Assets, Balance Sheet Groupings [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancialInstrumentsFinancialAssetsBalanceSheetGroupingsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial assets:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LoansReceivableFairValueDisclosure" xlink:label="us-gaap_LoansReceivableFairValueDisclosure" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LoansReceivableFairValueDisclosure" xlink:to="us-gaap_LoansReceivableFairValueDisclosure_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LoansReceivableFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Loans Receivable, Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LoansReceivableFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Net loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestReceivable" xlink:label="us-gaap_InterestReceivable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestReceivable" xlink:to="us-gaap_InterestReceivable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestReceivable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Receivable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestReceivable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Accrued interest receivable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:label="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract" xlink:to="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial Instruments, Financial Liabilities, Balance Sheet Groupings [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancialInstrumentsFinancialLiabilitiesBalanceSheetGroupingsAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financial liabilities:</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestBearingDepositLiabilities" xlink:label="us-gaap_InterestBearingDepositLiabilities" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestBearingDepositLiabilities" xlink:to="us-gaap_InterestBearingDepositLiabilities_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestBearingDepositLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest-bearing Deposit Liabilities</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestBearingDepositLiabilities_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest bearing deposits</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure" xlink:label="us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure" xlink:to="us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities Loaned or Sold under Agreements to Repurchase, Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SecuritiesLoanedOrSoldUnderAgreementsToRepurchaseFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities sold under repurchase agreements</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations" xlink:to="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subordinated Debt Obligations, Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:label="us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisSubordinatedDebtObligations_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Senior notes</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DebtInstrumentFairValue" xlink:label="us-gaap_DebtInstrumentFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DebtInstrumentFairValue" xlink:to="us-gaap_DebtInstrumentFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DebtInstrumentFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Debt Instrument, Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DebtInstrumentFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Note payable and other borrowings</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestPayableCurrentAndNoncurrent" xlink:label="us-gaap_InterestPayableCurrentAndNoncurrent" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestPayableCurrentAndNoncurrent" xlink:to="us-gaap_InterestPayableCurrentAndNoncurrent_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestPayableCurrentAndNoncurrent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Payable</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestPayableCurrentAndNoncurrent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Borrowing interest payable</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DepositInterestPayableFairValueDisclosure" xlink:label="osbc_DepositInterestPayableFairValueDisclosure" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DepositInterestPayableFairValueDisclosure" xlink:to="osbc_DepositInterestPayableFairValueDisclosure_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DepositInterestPayableFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the fair value of interest payable related to deposits at the balance sheet date.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DepositInterestPayableFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposit Interest Payable, Fair Value Disclosure</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DepositInterestPayableFairValueDisclosure_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deposit interest payable</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable" xlink:to="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValuesDerivativesBalanceSheetLocationByDerivativeContractTypeByHedgingDesignationTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet" xlink:label="us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet" xlink:to="us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestRateCashFlowHedgeGainLossToBeReclassifiedDuringNext12MonthsNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount to be reclassified as a reduction to interest expense during the next twelve months</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeNumberOfInstrumentsHeld" xlink:label="us-gaap_DerivativeNumberOfInstrumentsHeld" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeNumberOfInstrumentsHeld" xlink:to="us-gaap_DerivativeNumberOfInstrumentsHeld_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DerivativeNumberOfInstrumentsHeld_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivative, Number of Instruments Held</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeNumberOfInstrumentsHeld_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivative, number of transactions</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashFlowHedgeDerivativeInstrumentAssetsAtFairValue" xlink:label="us-gaap_CashFlowHedgeDerivativeInstrumentAssetsAtFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CashFlowHedgeDerivativeInstrumentAssetsAtFairValue" xlink:to="us-gaap_CashFlowHedgeDerivativeInstrumentAssetsAtFairValue_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CashFlowHedgeDerivativeInstrumentAssetsAtFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash Flow Hedge Derivative Instrument Assets at Fair Value</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CashFlowHedgeDerivativeInstrumentAssetsAtFairValue_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Derivative assets designated as hedging instruments, fair value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CashFlowHedgeDerivativeInstrumentLiabilitiesAtFairValue" xlink:label="us-gaap_CashFlowHedgeDerivativeInstrumentLiabilitiesAtFairValue" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_NumberOfFinancialInstitutionsInvestmentSecuritiesPledged" xlink:to="osbc_NumberOfFinancialInstitutionsInvestmentSecuritiesPledged_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_NumberOfFinancialInstitutionsInvestmentSecuritiesPledged_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the number of financial institutions where investment securities are pledged.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_NumberOfFinancialInstitutionsInvestmentSecuritiesPledged_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of Financial Institutions Investment Securities Pledged</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_NumberOfFinancialInstitutionsInvestmentSecuritiesPledged_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Number of correspondent financial institutions where investment securities are pledged</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet" xlink:label="us-gaap_InterestRateCashFlowHedgeGainLossReclassifiedToEarningsNet" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet" xlink:label="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet" xlink:to="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DerivativeInstrumentsNotDesignatedAsHedgingInstrumentsGainLossNet_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Amount of Gain or (Loss) Recognized in Income on Derivative</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ScheduleOfPreferredStockTable" xlink:label="osbc_ScheduleOfPreferredStockTable" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ClassOfStockDomain" xlink:label="us-gaap_ClassOfStockDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ClassOfStockDomain" xlink:to="us-gaap_ClassOfStockDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SeriesBPreferredStockMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Series B Preferred Stock [Member]</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_WarrantMember" xlink:to="us-gaap_WarrantMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_WarrantMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Warrant [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_WarrantMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Warrants</label>
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_PreferredStockLineItems" xlink:to="osbc_PreferredStockLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_PreferredStockLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Preferred Stock [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_PreferredStockLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Preferred Stock</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ClassOfWarrantOrRightTerm" xlink:label="osbc_ClassOfWarrantOrRightTerm" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ClassOfWarrantOrRightTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Period representing the term of warrant.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ClassOfWarrantOrRightTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Class of Warrant or Right Term</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ClassOfWarrantOrRightTerm_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Warrants, term</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StockRedeemedOrCalledDuringPeriodShares_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stock Redeemed or Called During Period, Shares</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_StockRedeemedOrCalledDuringPeriodShares_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Shares redeemed (in shares)</label>
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Preferred Stock, Shares Authorized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PreferredStockSharesAuthorized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Preferred stock, Shares authorized</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ParentCompanyMember" xlink:label="srt_ParentCompanyMember" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures" xlink:to="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investments in and Advance to Affiliates, Subsidiaries, Associates, and Joint Ventures</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Investment in subsidiaries</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:to="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Liabilities and Equity [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LiabilitiesAndStockholdersEquityAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Liabilities and Stockholders' Equity</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CondensedIncomeStatementTable" xlink:label="srt_CondensedIncomeStatementTable" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CondensedIncomeStatementsCaptionsLineItems" xlink:label="srt_CondensedIncomeStatementsCaptionsLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_CondensedIncomeStatementsCaptionsLineItems" xlink:to="srt_CondensedIncomeStatementsCaptionsLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_CondensedIncomeStatementsCaptionsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Condensed Income Statements, Captions [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_CondensedIncomeStatementsCaptionsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Condensed statements of Income</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OperatingIncomeAbstract" xlink:label="osbc_OperatingIncomeAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OperatingIncomeAbstract" xlink:to="osbc_OperatingIncomeAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OperatingIncomeAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Income [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OperatingIncomeAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Income</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DividendsReceivedFromConsolidatedSubsidiaries" xlink:label="osbc_DividendsReceivedFromConsolidatedSubsidiaries" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DividendsReceivedFromConsolidatedSubsidiaries" xlink:to="osbc_DividendsReceivedFromConsolidatedSubsidiaries_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DividendsReceivedFromConsolidatedSubsidiaries_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the amount paid by consolidated subsidiaries to the parent company.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DividendsReceivedFromConsolidatedSubsidiaries_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Dividends Received From Consolidated Subsidiaries</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DividendsReceivedFromConsolidatedSubsidiaries_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Cash dividends received from subsidiaries</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherOperatingIncome" xlink:label="us-gaap_OtherOperatingIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherOperatingIncome" xlink:to="us-gaap_OtherOperatingIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherOperatingIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Operating Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherOperatingIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other income</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OperatingIncome" xlink:label="osbc_OperatingIncome" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OperatingIncome" xlink:to="osbc_OperatingIncome_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OperatingIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">The total amount of operating income from items that are associated with the entity's normal revenue producing operation.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OperatingIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Income</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="osbc_OperatingIncome_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total operating income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingExpensesAbstract" xlink:label="us-gaap_OperatingExpensesAbstract" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpensesAbstract" xlink:to="us-gaap_OperatingExpensesAbstract_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Expenses [Abstract]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OperatingExpensesAbstract_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Expenses</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestExpenseOther" xlink:label="us-gaap_InterestExpenseOther" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestExpenseOther" xlink:to="us-gaap_InterestExpenseOther_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestExpenseOther_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Expense, Other</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestExpenseOther_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other interest expense</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherCostAndExpenseOperating" xlink:label="us-gaap_OtherCostAndExpenseOperating" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherCostAndExpenseOperating" xlink:to="us-gaap_OtherCostAndExpenseOperating_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherCostAndExpenseOperating_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Cost and Expense, Operating</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherCostAndExpenseOperating_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other expenses</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OperatingExpenses" xlink:label="us-gaap_OperatingExpenses" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OperatingExpenses" xlink:to="us-gaap_OperatingExpenses_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OperatingExpenses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Operating Expenses</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="us-gaap_OperatingExpenses_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total operating expense</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:label="osbc_IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments" xlink:to="osbc_IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Sum of operating profit and nonoperating income or expense after tax but before Income or Loss from equity method investments, extraordinary items, and noncontrolling interest.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income (Loss) from Continuing Operations after Income Taxes before Minority Interest and Income (Loss) from Equity Method Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:label="osbc_IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income (loss) before equity in undistributed net income of subsidiaries</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeLossFromEquityMethodInvestments" xlink:to="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income (Loss) from Equity Method Investments</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity in undistributed net income of subsidiaries</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeLossFromEquityMethodInvestments_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Equity in undistributed net income of subsidiaries</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CondensedCashFlowStatementTable" xlink:label="srt_CondensedCashFlowStatementTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_CondensedCashFlowStatementTable" xlink:to="srt_CondensedCashFlowStatementTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_CondensedCashFlowStatementTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Condensed Cash Flow Statement [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:label="srt_CondensedCashFlowStatementsCaptionsLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_CondensedCashFlowStatementsCaptionsLineItems" xlink:to="srt_CondensedCashFlowStatementsCaptionsLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_CondensedCashFlowStatementsCaptionsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Condensed Cash Flow Statements, Captions [Line Items]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_CondensedCashFlowStatementsCaptionsLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Condensed statements of cash flows</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncreaseDecreaseInOtherCurrentAssets" xlink:label="us-gaap_IncreaseDecreaseInOtherCurrentAssets" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncreaseDecreaseInOtherCurrentAssets" xlink:to="us-gaap_IncreaseDecreaseInOtherCurrentAssets_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncreaseDecreaseInOtherCurrentAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Increase (Decrease) in Other Current Assets</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:label="us-gaap_IncreaseDecreaseInOtherCurrentAssets_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Change in other assets</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherOperatingActivitiesCashFlowStatement" xlink:label="us-gaap_OtherOperatingActivitiesCashFlowStatement" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherOperatingActivitiesCashFlowStatement" xlink:to="us-gaap_OtherOperatingActivitiesCashFlowStatement_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherOperatingActivitiesCashFlowStatement_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Operating Activities, Cash Flow Statement</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherOperatingActivitiesCashFlowStatement_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other, net</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedContributionPlanTable" xlink:label="us-gaap_DefinedContributionPlanTable" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanTable" xlink:to="us-gaap_DefinedContributionPlanTable_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DefinedContributionPlanTable_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Defined Contribution Plan [Table]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedContributionPlanDisclosureLineItems" xlink:label="us-gaap_DefinedContributionPlanDisclosureLineItems" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanDisclosureLineItems" xlink:to="us-gaap_DefinedContributionPlanDisclosureLineItems_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DefinedContributionPlanDisclosureLineItems_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Employee Benefit Plans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch" xlink:to="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Defined Contribution Plan, Employer Matching Contribution, Percent of Match</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Company's discretionary matching contributions to the Plan (as a percent)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo" xlink:label="osbc_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo" xlink:to="osbc_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Second percentage employer matches of the employee's percentage contribution matched.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Defined Contribution Plan, Employer Matching Contribution, Percent of Match, Two</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Company's discretionary matching contributions to the Plan (as a percent)</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent" xlink:to="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Defined Contribution Plan, Employer Matching Contribution, Percent of Employees' Gross Pay</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Percentage of compensation contributed to the Plan matched by employer</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage" xlink:label="us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage" xlink:to="us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Defined Contribution Plan, Employers Matching Contribution, Annual Vesting Percentage</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DefinedContributionPlanEmployersMatchingContributionAnnualVestingPercentage_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Participants vesting as percentage of discretionary matching contributions</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DefinedContributionPlanCostRecognized" xlink:label="us-gaap_DefinedContributionPlanCostRecognized" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DefinedContributionPlanCostRecognized" xlink:to="us-gaap_DefinedContributionPlanCostRecognized_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DefinedContributionPlanCostRecognized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Defined Contribution Plan, Cost Recognized</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DefinedContributionPlanCostRecognized_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Expense relating to the 401(k) plan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent" xlink:to="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Deferred Compensation Liability, Current and Noncurrent</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Company obligations under Voluntary Deferred Compensation Plan for Executives</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductOrServiceAxis" xlink:label="srt_ProductOrServiceAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ProductOrServiceAxis" xlink:to="srt_ProductOrServiceAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_ProductOrServiceAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Product and Service [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_ProductsAndServicesDomain" xlink:label="srt_ProductsAndServicesDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_ProductsAndServicesDomain" xlink:to="srt_ProductsAndServicesDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_ProductsAndServicesDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Products And Services [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_ProductsAndServicesDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Product and Service [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiduciaryAndTrustMember" xlink:label="us-gaap_FiduciaryAndTrustMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FiduciaryAndTrustMember" xlink:to="us-gaap_FiduciaryAndTrustMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FiduciaryAndTrustMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Fiduciary And Trust [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FiduciaryAndTrustMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Trust Income</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BankServicingMember" xlink:label="us-gaap_BankServicingMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BankServicingMember" xlink:to="us-gaap_BankServicingMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BankServicingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Bank Servicing [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BankServicingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Bank Servicing</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageBankingMember" xlink:label="us-gaap_MortgageBankingMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MortgageBankingMember" xlink:to="us-gaap_MortgageBankingMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MortgageBankingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Banking [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MortgageBankingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Secondary mortgage fees</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_MortgageServicingMember" xlink:label="osbc_MortgageServicingMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_MortgageServicingMember" xlink:to="osbc_MortgageServicingMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_MortgageServicingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage servicing income.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_MortgageServicingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Servicing [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_MortgageServicingMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Servicing</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_TreasuryStockCommonMember" xlink:label="us-gaap_TreasuryStockCommonMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_TreasuryStockCommonMember" xlink:to="us-gaap_TreasuryStockCommonMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_TreasuryStockCommonMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Treasury Stock Common [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_TreasuryStockCommonMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Treasury Stock</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAxis" xlink:label="us-gaap_BusinessAcquisitionAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionAxis" xlink:to="us-gaap_BusinessAcquisitionAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Business Acquisition [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_BusinessAcquisitionAcquireeDomain" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_BusinessAcquisitionAcquireeDomain" xlink:to="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Business Acquisition Acquiree [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_BusinessAcquisitionAcquireeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Business Acquisition, Acquiree [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_TalmerBancorpInc.Member" xlink:label="osbc_TalmerBancorpInc.Member" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_TalmerBancorpInc.Member" xlink:to="osbc_TalmerBancorpInc.Member_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_TalmerBancorpInc.Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the name of the acquired entity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_TalmerBancorpInc.Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Talmer Bancorp Inc. [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_TalmerBancorpInc.Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Talmer</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis" xlink:to="us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentByClassOfFinancingReceivableAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Class of Financing Receivable [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain" xlink:to="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivable Recorded Investment Class Of Financing Receivable [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivableRecordedInvestmentClassOfFinancingReceivableDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Class of Financing Receivable [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ConstructionLoansMember" xlink:label="us-gaap_ConstructionLoansMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ConstructionLoansMember" xlink:to="us-gaap_ConstructionLoansMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ConstructionLoansMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Construction Loans [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ConstructionLoansMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Construction Loans</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeAxis" xlink:label="us-gaap_SubsequentEventTypeAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsequentEventTypeAxis" xlink:to="us-gaap_SubsequentEventTypeAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SubsequentEventTypeAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subsequent Event Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventTypeDomain" xlink:label="us-gaap_SubsequentEventTypeDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubsequentEventTypeDomain" xlink:to="us-gaap_SubsequentEventTypeDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SubsequentEventTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subsequent Event Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SubsequentEventTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subsequent Event Type [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubsequentEventMember" xlink:label="us-gaap_SubsequentEventMember" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xlink:label="us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CoreDepositsMember" xlink:label="us-gaap_CoreDepositsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CoreDepositsMember" xlink:to="us-gaap_CoreDepositsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CoreDepositsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Core Deposits [Member]</label>
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    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationAxis" xlink:label="us-gaap_IncomeStatementLocationAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementLocationAxis" xlink:to="us-gaap_IncomeStatementLocationAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeStatementLocationAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Statement Location [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_IncomeStatementLocationDomain" xlink:label="us-gaap_IncomeStatementLocationDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_IncomeStatementLocationDomain" xlink:to="us-gaap_IncomeStatementLocationDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Statement Location [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_IncomeStatementLocationDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Income Statement Location [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SellingGeneralAndAdministrativeExpensesMember" xlink:to="us-gaap_SellingGeneralAndAdministrativeExpensesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Selling General And Administrative Expenses [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SellingGeneralAndAdministrativeExpensesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Selling, General and Administrative Expenses [Member]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_SalariesAndEmployeeBenefitsMember" xlink:label="osbc_SalariesAndEmployeeBenefitsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_SalariesAndEmployeeBenefitsMember" xlink:to="osbc_SalariesAndEmployeeBenefitsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_SalariesAndEmployeeBenefitsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Salaries and employee benefits.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_SalariesAndEmployeeBenefitsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Salaries And Employee Benefits [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_SalariesAndEmployeeBenefitsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Salaries and Employee Benefits</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_InformationTechnologyAndOtherMember" xlink:label="osbc_InformationTechnologyAndOtherMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_InformationTechnologyAndOtherMember" xlink:to="osbc_InformationTechnologyAndOtherMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_InformationTechnologyAndOtherMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Data processing, computer and ATM related expenses.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_InformationTechnologyAndOtherMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Information Technology And Other [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_InformationTechnologyAndOtherMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Data Processing, Computer and ATM</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_USTreasuryAndGovernmentMember" xlink:label="us-gaap_USTreasuryAndGovernmentMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_USTreasuryAndGovernmentMember" xlink:to="us-gaap_USTreasuryAndGovernmentMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_USTreasuryAndGovernmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">U S Treasury And Government [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_USTreasuryAndGovernmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">US Treasury and Government</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember" xlink:label="us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember" xlink:to="us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Backed Securities Issued By U S Government Sponsored Enterprises [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">U.S. government agencies mortgage-backed</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CollateralizedLoanObligationsMember" xlink:label="us-gaap_CollateralizedLoanObligationsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CollateralizedLoanObligationsMember" xlink:to="us-gaap_CollateralizedLoanObligationsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CollateralizedLoanObligationsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Collateralized Loan Obligations [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CollateralizedLoanObligationsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Collateralized loan obligations</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_StatementScenarioAxis" xlink:label="us-gaap_StatementScenarioAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_StatementScenarioAxis" xlink:to="us-gaap_StatementScenarioAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_StatementScenarioAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Scenario [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ScenarioUnspecifiedDomain" xlink:label="us-gaap_ScenarioUnspecifiedDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ScenarioUnspecifiedDomain" xlink:to="us-gaap_ScenarioUnspecifiedDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ScenarioUnspecifiedDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Scenario Unspecified [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ScenarioUnspecifiedDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Scenario, Unspecified [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_ProFormaMember" xlink:label="us-gaap_ProFormaMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_ProFormaMember" xlink:to="us-gaap_ProFormaMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_ProFormaMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pro Forma [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_ProFormaMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pro Forma</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ReimbursementRequestsGreaterThan5PercentMember" xlink:label="osbc_ReimbursementRequestsGreaterThan5PercentMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ReimbursementRequestsGreaterThan5PercentMember" xlink:to="osbc_ReimbursementRequestsGreaterThan5PercentMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ReimbursementRequestsGreaterThan5PercentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Information related to reimbursement requests greater than 5 percent.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ReimbursementRequestsGreaterThan5PercentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Reimbursement Requests Greater Than5 Percent [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ReimbursementRequestsGreaterThan5PercentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Reimbursement requests greater than 5 %</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ReimbursementRequestsGreaterThan9PercentMember" xlink:label="osbc_ReimbursementRequestsGreaterThan9PercentMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ReimbursementRequestsGreaterThan9PercentMember" xlink:to="osbc_ReimbursementRequestsGreaterThan9PercentMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ReimbursementRequestsGreaterThan9PercentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Information related to reimbursement requests greater than 9 %.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ReimbursementRequestsGreaterThan9PercentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Reimbursement Requests Greater Than9 Percent [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ReimbursementRequestsGreaterThan9PercentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Reimbursement requests greater than 9 %</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CreditConcentrationRiskMember" xlink:label="us-gaap_CreditConcentrationRiskMember" xmlns="http://www.xbrl.org/2003/linkbase" />
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    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CreditConcentrationRiskMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Credit Concentration Risk [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CreditConcentrationRiskMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Credit Concentration Risk</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_MortgageBackedAndCollateralizedMortgageObligationsMember" xlink:label="osbc_MortgageBackedAndCollateralizedMortgageObligationsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_MortgageBackedAndCollateralizedMortgageObligationsMember" xlink:to="osbc_MortgageBackedAndCollateralizedMortgageObligationsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_MortgageBackedAndCollateralizedMortgageObligationsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Securities collateralized by mortgage loans and other collateral.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_MortgageBackedAndCollateralizedMortgageObligationsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Backed And Collateralized Mortgage Obligations [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_MortgageBackedAndCollateralizedMortgageObligationsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage-backed and collateralized mortgage obligations</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueAxis" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivablesPeriodPastDueAxis" xlink:to="us-gaap_FinancingReceivablesPeriodPastDueAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivables, Period Past Due [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesPeriodPastDueDomain" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivablesPeriodPastDueDomain" xlink:to="us-gaap_FinancingReceivablesPeriodPastDueDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivables Period Past Due [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivablesPeriodPastDueDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivables, Period Past Due [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivables30To59DaysPastDueMember" xlink:label="us-gaap_FinancingReceivables30To59DaysPastDueMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivables30To59DaysPastDueMember" xlink:to="us-gaap_FinancingReceivables30To59DaysPastDueMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivables30To59DaysPastDueMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivables30 To59 Days Past Due [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivables30To59DaysPastDueMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">30 to 59 Days Past Due</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivables60To89DaysPastDueMember" xlink:label="us-gaap_FinancingReceivables60To89DaysPastDueMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivables60To89DaysPastDueMember" xlink:to="us-gaap_FinancingReceivables60To89DaysPastDueMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivables60To89DaysPastDueMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivables60 To89 Days Past Due [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivables60To89DaysPastDueMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">60 to 89 Days Past Due</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember" xlink:label="us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember" xlink:to="us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Financing Receivables Equal To Greater Than90 Days Past Due [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinancingReceivablesEqualToGreaterThan90DaysPastDueMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">90 Days or Greater Past Due</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_RealEstatePortfolioSegmentMember" xlink:label="osbc_RealEstatePortfolioSegmentMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_RealEstatePortfolioSegmentMember" xlink:to="osbc_RealEstatePortfolioSegmentMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_RealEstatePortfolioSegmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Portfolio segment of the company's total financing receivable related to real estate including commercial and residential.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_RealEstatePortfolioSegmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Real Estate Portfolio Segment [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_RealEstatePortfolioSegmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total real estate</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FinanceLeasesPortfolioSegmentMember" xlink:label="us-gaap_FinanceLeasesPortfolioSegmentMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FinanceLeasesPortfolioSegmentMember" xlink:to="us-gaap_FinanceLeasesPortfolioSegmentMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FinanceLeasesPortfolioSegmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Finance Leases Portfolio Segment [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_FinanceLeasesPortfolioSegmentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Lease financing receivables</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OtherFinancingReceivableMember" xlink:label="osbc_OtherFinancingReceivableMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OtherFinancingReceivableMember" xlink:to="osbc_OtherFinancingReceivableMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OtherFinancingReceivableMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivables related to other financing receivables.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OtherFinancingReceivableMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Financing Receivable [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OtherFinancingReceivableMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_HomeEquityMember" xlink:label="us-gaap_HomeEquityMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_HomeEquityMember" xlink:to="us-gaap_HomeEquityMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_HomeEquityMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Home Equity [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_HomeEquityMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Home Equity Line of Credit</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ConstructionRealEstateHomebuilderLoanMember" xlink:label="osbc_ConstructionRealEstateHomebuilderLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ConstructionRealEstateHomebuilderLoanMember" xlink:to="osbc_ConstructionRealEstateHomebuilderLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ConstructionRealEstateHomebuilderLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to homebuilder construction real estate.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ConstructionRealEstateHomebuilderLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Construction Real Estate Homebuilder Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ConstructionRealEstateHomebuilderLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Homebuilder</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ConstructionRealEstateLandLoanMember" xlink:label="osbc_ConstructionRealEstateLandLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ConstructionRealEstateLandLoanMember" xlink:to="osbc_ConstructionRealEstateLandLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ConstructionRealEstateLandLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to construction real estate land.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ConstructionRealEstateLandLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Construction Real Estate Land Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ConstructionRealEstateLandLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Land</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_MultiFamilyLoanMember" xlink:label="osbc_MultiFamilyLoanMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_MultiFamilyLoanMember" xlink:to="osbc_MultiFamilyLoanMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_MultiFamilyLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the class of financing receivable related to loans on multifamily homes.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_MultiFamilyLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Multi Family Loan [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_MultiFamilyLoanMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Multifamily</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PassMember" xlink:label="us-gaap_PassMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PassMember" xlink:to="us-gaap_PassMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PassMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pass [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PassMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Pass</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SpecialMentionMember" xlink:label="us-gaap_SpecialMentionMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SpecialMentionMember" xlink:to="us-gaap_SpecialMentionMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SpecialMentionMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Special Mention [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SpecialMentionMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Special Mention</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SubstandardMember" xlink:label="us-gaap_SubstandardMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SubstandardMember" xlink:to="us-gaap_SubstandardMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SubstandardMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Substandard [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SubstandardMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Substandard</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis" xlink:to="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RelatedPartyTransactionsByRelatedPartyAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Related Party [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RelatedPartyDomain" xlink:label="us-gaap_RelatedPartyDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RelatedPartyDomain" xlink:to="us-gaap_RelatedPartyDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RelatedPartyDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Related Party [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RelatedPartyDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Related Party [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_ManagementAndAffiliatesMember" xlink:label="osbc_ManagementAndAffiliatesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_ManagementAndAffiliatesMember" xlink:to="osbc_ManagementAndAffiliatesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_ManagementAndAffiliatesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Person or persons controlling and directing the affairs of an entity, and their affiliates.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_ManagementAndAffiliatesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Management And Affiliates [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_ManagementAndAffiliatesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Principal Officers, Directors, and Affiliates</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_SeniorNotesMember" xlink:label="us-gaap_SeniorNotesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_SeniorNotesMember" xlink:to="us-gaap_SeniorNotesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_SeniorNotesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Senior Notes [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_SeniorNotesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Senior Notes.</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalHomeLoanBankAdvancesAt142PercentageMember" xlink:label="osbc_FederalHomeLoanBankAdvancesAt142PercentageMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalHomeLoanBankAdvancesAt142PercentageMember" xlink:to="osbc_FederalHomeLoanBankAdvancesAt142PercentageMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalHomeLoanBankAdvancesAt142PercentageMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Information related to Federal Home Loan Bank Advances at 1.42 %.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalHomeLoanBankAdvancesAt142PercentageMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Advances At142 Percentage [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalHomeLoanBankAdvancesAt142PercentageMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FHLB advances at 1.42 %</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_FederalHomeLoanBankAdvancesAt144PercentageMember" xlink:label="osbc_FederalHomeLoanBankAdvancesAt144PercentageMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_FederalHomeLoanBankAdvancesAt144PercentageMember" xlink:to="osbc_FederalHomeLoanBankAdvancesAt144PercentageMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_FederalHomeLoanBankAdvancesAt144PercentageMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Information related to Federal Home Loan Bank Advances At 1.44 %.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_FederalHomeLoanBankAdvancesAt144PercentageMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Federal Home Loan Bank Advances At144 Percentage [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_FederalHomeLoanBankAdvancesAt144PercentageMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">FHLB advances at 1.44 %</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CreditFacilityMember" xlink:label="osbc_CreditFacilityMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CreditFacilityMember" xlink:to="osbc_CreditFacilityMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CreditFacilityMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the credit facility available from a bank, which consisted of senior debt facility and subordinated debt.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CreditFacilityMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Credit Facility [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CreditFacilityMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Correspondent Bank</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_SeniorDebtFacilityMember" xlink:label="osbc_SeniorDebtFacilityMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_SeniorDebtFacilityMember" xlink:to="osbc_SeniorDebtFacilityMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_SeniorDebtFacilityMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents the senior debt facility which consists of a revolving line of credit, a term loan and subordinated debt.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_SeniorDebtFacilityMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Senior Debt Facility [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_SeniorDebtFacilityMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Senior debt facility</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableRateAxis" xlink:label="us-gaap_VariableRateAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VariableRateAxis" xlink:to="us-gaap_VariableRateAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_VariableRateAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Variable Rate [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_VariableRateDomain" xlink:label="us-gaap_VariableRateDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_VariableRateDomain" xlink:to="us-gaap_VariableRateDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_VariableRateDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Variable Rate [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_VariableRateDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Variable Rate [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_LondonInterbankOfferedRateLIBORMember" xlink:to="us-gaap_LondonInterbankOfferedRateLIBORMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">London Interbank Offered Rate L I B O R [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_LondonInterbankOfferedRateLIBORMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Three month LIBOR</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OldSecondCapitalTrustIIMember" xlink:label="osbc_OldSecondCapitalTrustIIMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OldSecondCapitalTrustIIMember" xlink:to="osbc_OldSecondCapitalTrustIIMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OldSecondCapitalTrustIIMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents Old Second Capital Trust II, an unconsolidated subsidiary of the entity.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OldSecondCapitalTrustIIMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Old Second Capital Trust I I [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OldSecondCapitalTrustIIMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Old Second Capital Trust II</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_StockOptionPlan2009Member" xlink:label="osbc_StockOptionPlan2009Member" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_StockOptionPlan2009Member" xlink:to="osbc_StockOptionPlan2009Member_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_StockOptionPlan2009Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents activity related to 2009 plan.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_StockOptionPlan2009Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Stock Option Plan2009 [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_StockOptionPlan2009Member_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">2009 Plan</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis" xlink:to="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Antidilutive Securities [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_AntidilutiveSecuritiesNameDomain" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_AntidilutiveSecuritiesNameDomain" xlink:to="us-gaap_AntidilutiveSecuritiesNameDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Antidilutive Securities Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_AntidilutiveSecuritiesNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Antidilutive Securities, Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_SubsidiariesMember" xlink:label="srt_SubsidiariesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_SubsidiariesMember" xlink:to="srt_SubsidiariesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_SubsidiariesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Subsidiaries [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_SubsidiariesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Old Second National Bank</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MortgageBackedSecuritiesMember" xlink:label="us-gaap_MortgageBackedSecuritiesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MortgageBackedSecuritiesMember" xlink:to="us-gaap_MortgageBackedSecuritiesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MortgageBackedSecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Mortgage Backed Securities [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MortgageBackedSecuritiesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Collateralized mortgage obligation ("MBS")</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MeasurementInputTypeAxis" xlink:label="us-gaap_MeasurementInputTypeAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MeasurementInputTypeAxis" xlink:to="us-gaap_MeasurementInputTypeAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MeasurementInputTypeAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Input Type [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MeasurementInputTypeDomain" xlink:label="us-gaap_MeasurementInputTypeDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MeasurementInputTypeDomain" xlink:to="us-gaap_MeasurementInputTypeDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MeasurementInputTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Input Type [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MeasurementInputTypeDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Input Type [Domain]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MeasurementInputDiscountRateMember" xlink:label="us-gaap_MeasurementInputDiscountRateMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MeasurementInputDiscountRateMember" xlink:to="us-gaap_MeasurementInputDiscountRateMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MeasurementInputDiscountRateMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Input Discount Rate [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MeasurementInputDiscountRateMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Input, Discount Rate</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_MeasurementInputConstantPrepaymentRateMember" xlink:label="us-gaap_MeasurementInputConstantPrepaymentRateMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_MeasurementInputConstantPrepaymentRateMember" xlink:to="us-gaap_MeasurementInputConstantPrepaymentRateMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_MeasurementInputConstantPrepaymentRateMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Input Constant Prepayment Rate [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_MeasurementInputConstantPrepaymentRateMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Input, Constant Prepayment Rate</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_FairValueByMeasurementBasisAxis" xlink:label="us-gaap_FairValueByMeasurementBasisAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_FairValueByMeasurementBasisAxis" xlink:to="us-gaap_FairValueByMeasurementBasisAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_FairValueByMeasurementBasisAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Measurement Basis [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_PortionAtFairValueFairValueDisclosureMember" xlink:to="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Portion At Fair Value Fair Value Disclosure [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_PortionAtFairValueFairValueDisclosureMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Portion at Fair Value Measurement [Member]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:to="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Carrying Reported Amount Fair Value Disclosure [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_CarryingReportedAmountFairValueDisclosureMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Carrying Amount</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:to="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Estimate Of Fair Value Fair Value Disclosure [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_EstimateOfFairValueFairValueDisclosureMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Total Fair Value</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_DesignatedAsHedgingInstrumentMember" xlink:label="us-gaap_DesignatedAsHedgingInstrumentMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_DesignatedAsHedgingInstrumentMember" xlink:to="us-gaap_DesignatedAsHedgingInstrumentMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_DesignatedAsHedgingInstrumentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Designated As Hedging Instrument [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_DesignatedAsHedgingInstrumentMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Designated</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_InterestRateContractMember" xlink:label="us-gaap_InterestRateContractMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_InterestRateContractMember" xlink:to="us-gaap_InterestRateContractMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_InterestRateContractMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Rate Contract [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_InterestRateContractMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Rate Products</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_InterestRateLockCommitmentsAndForwardContractsMember" xlink:label="osbc_InterestRateLockCommitmentsAndForwardContractsMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_InterestRateLockCommitmentsAndForwardContractsMember" xlink:to="osbc_InterestRateLockCommitmentsAndForwardContractsMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_InterestRateLockCommitmentsAndForwardContractsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commitments to extend credit where the interest rate is locked in advance of funds being disbursed for a specified period of time, and contracts negotiated between two parties to purchase and sell a specific quantity of a financial instrument, foreign currency, or commodity at a price specified at origination of the contract, with delivery and settlement at a specified future date.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_InterestRateLockCommitmentsAndForwardContractsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Rate Lock Commitments And Forward Contracts [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_InterestRateLockCommitmentsAndForwardContractsMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Interest Rate Lock Commitments and Forward Contracts</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_OtherContractMember" xlink:label="us-gaap_OtherContractMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_OtherContractMember" xlink:to="us-gaap_OtherContractMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_OtherContractMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Contract [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_OtherContractMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Other Contracts</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_CounterpartyNameAxis" xlink:label="srt_CounterpartyNameAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_CounterpartyNameAxis" xlink:to="srt_CounterpartyNameAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_CounterpartyNameAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Counterparty Name [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd#srt_RepurchaseAgreementCounterpartyNameDomain" xlink:label="srt_RepurchaseAgreementCounterpartyNameDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="srt_RepurchaseAgreementCounterpartyNameDomain" xlink:to="srt_RepurchaseAgreementCounterpartyNameDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="srt_RepurchaseAgreementCounterpartyNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Repurchase Agreement Counterparty Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="srt_RepurchaseAgreementCounterpartyNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Counterparty Name [Domain]</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_CommercialLoanCustomersMember" xlink:label="osbc_CommercialLoanCustomersMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_CommercialLoanCustomersMember" xlink:to="osbc_CommercialLoanCustomersMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_CommercialLoanCustomersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Information pertaining to commercial loan customers.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_CommercialLoanCustomersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial Loan Customers [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_CommercialLoanCustomersMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Commercial Loan Customers</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OsbcAffiliatesMember" xlink:label="osbc_OsbcAffiliatesMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OsbcAffiliatesMember" xlink:to="osbc_OsbcAffiliatesMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OsbcAffiliatesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Information pertaining to OSBC affiliates.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OsbcAffiliatesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Osbc Affiliates [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OsbcAffiliatesMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">OSBC Affiliates</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetirementPlanNameAxis" xlink:label="us-gaap_RetirementPlanNameAxis" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetirementPlanNameAxis" xlink:to="us-gaap_RetirementPlanNameAxis_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RetirementPlanNameAxis_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Retirement Plan Name [Axis]</label>
    <loc xlink:type="locator" xlink:href="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd#us-gaap_RetirementPlanNameDomain" xlink:label="us-gaap_RetirementPlanNameDomain" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="us-gaap_RetirementPlanNameDomain" xlink:to="us-gaap_RetirementPlanNameDomain_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="us-gaap_RetirementPlanNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Retirement Plan Name [Domain]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="us-gaap_RetirementPlanNameDomain_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Defined Contribution Plan Name [Domain] (Deprecated 2017-01-31)</label>
    <loc xlink:type="locator" xlink:href="osbc-20181231.xsd#osbc_OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember" xlink:label="osbc_OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember" xmlns="http://www.xbrl.org/2003/linkbase" />
    <labelArc xlink:type="arc" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="osbc_OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember" xlink:to="osbc_OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember_lbl" xmlns="http://www.xbrl.org/2003/linkbase" />
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:label="osbc_OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Represents activity related to the Old Second Bancorp, Inc. Employees 401(k) Savings Plan and Trust, a qualified, tax-exempt defined contribution plan.</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/label" xlink:label="osbc_OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Old Second Bancorp Inc Employees401 K Savings Plan And Trust [Member]</label>
    <label xlink:type="resource" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:label="osbc_OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember_lbl" xml:lang="en-US" xmlns="http://www.xbrl.org/2003/linkbase">Old Second Bancorp Inc Employees 401(k) Savings Plan and Trust</label>
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