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  <import namespace="http://fasb.org/us-gaap/2018-01-31" schemaLocation="http://xbrl.fasb.org/us-gaap/2018/elts/us-gaap-2018-01-31.xsd" xmlns="http://www.w3.org/2001/XMLSchema" />
  <import namespace="http://fasb.org/srt/2018-01-31" schemaLocation="http://xbrl.fasb.org/srt/2018/elts/srt-2018-01-31.xsd" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="false" id="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCostWeightedAverageYield" name="AvailableForSaleSecuritiesDebtMaturitiesAfterOneThroughFiveYearsAmortizedCostWeightedAverageYield" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield" name="AvailableForSaleSecuritiesDebtMaturitiesAfterFiveThroughTenYearsAmortizedCostWeightedAverageYield" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield" name="AvailableForSaleSecuritiesDebtMaturitiesAfterTenYearsAmortizedCostWeightedAverageYield" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_CardInterchangeIncomeDebit" name="CardInterchangeIncomeDebit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeathBenefitRealizedOnBankOwnedLifeInsurance" name="DeathBenefitRealizedOnBankOwnedLifeInsurance" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="osbc_DebitCardInterchangeExpense" name="DebitCardInterchangeExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="osbc_OtherRealEstateOwnedExpense" name="OtherRealEstateOwnedExpense" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <element id="osbc_IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets" name="IncreaseDecreaseInAccruedInterestReceivableAndOtherAssets" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="false" id="osbc_IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities" name="IncreaseDecreaseInAccruedInterestPayableAndOtherLiabilities" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <element id="osbc_DeathClaimOnBankOwnedLifeInsurance" name="DeathClaimOnBankOwnedLifeInsurance" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element id="osbc_InterestPaidForDeposits" name="InterestPaidForDeposits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_LoansDisclosureAbstract" name="LoansDisclosureAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_LoansTextBlock" name="LoansTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_AllowanceForLoanLossesDisclosureAbstract" name="AllowanceForLoanLossesDisclosureAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_AllowanceForLoanLossesTextBlock" name="AllowanceForLoanLossesTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_FairValuesOfFinancialInstrumentsDisclosureAbstract" name="FairValuesOfFinancialInstrumentsDisclosureAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_FairValuesOfFinancialInstrumentsDisclosureTextBlock" name="FairValuesOfFinancialInstrumentsDisclosureTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_DocumentAndEntityInformationAbstract" name="DocumentAndEntityInformationAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_MortgageBankingDerivativesDisclosureAbstract" name="MortgageBankingDerivativesDisclosureAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_NonCashTransferOfPremisesToOtherRealEstateOwned" name="NonCashTransferOfPremisesToOtherRealEstateOwned" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="osbc_OtherRealEstateValuationAllowanceRollForwardTableTextBlock" name="OtherRealEstateValuationAllowanceRollForwardTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_OtherRealEstateExpensesRelatedToForeclosedAssetsTableTextBlock" name="OtherRealEstateExpensesRelatedToForeclosedAssetsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_ForeclosedRealEstateExpenseNetOfLeaseRevenue" name="ForeclosedRealEstateExpenseNetOfLeaseRevenue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_OtherRealEstateOwnedExpensesRelatedToForeclosedAssetsAbstract" name="OtherRealEstateOwnedExpensesRelatedToForeclosedAssetsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_ScheduleOfDepositsTableTextBlock" name="ScheduleOfDepositsTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember" name="MortgageBackedSecuritiesIssuedByUSGovernmentAgenciesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis" name="AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateAmortizedCostBasis" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield" name="AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateWeightedAverageYield" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield" name="AvailableForSaleSecuritiesDebtMaturitiesWithoutSingleMaturityDateWeightedAverageYield" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_AvailableForSaleSecuritiesWeightedAverageYield" name="AvailableForSaleSecuritiesWeightedAverageYield" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue" name="AvailableForSaleDebtMaturitiesBeforeSecuritiesWithoutSingleMaturityDateFairValue" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="osbc_AvailableForSaleSecuritiesInUnrealizedLossPositionLessThan12MonthsQualitativeDisclosureNumberOfPositions" name="AvailableForSaleSecuritiesInUnrealizedLossPositionLessThan12MonthsQualitativeDisclosureNumberOfPositions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="instant" />
  <xsd:element id="osbc_AvailableForSaleSecuritiesInUnrealizedLossPositions12MonthsOrLongerQualitativeDisclosureNumberOfPositions" name="AvailableForSaleSecuritiesInUnrealizedLossPositions12MonthsOrLongerQualitativeDisclosureNumberOfPositions" nillable="true" substitutionGroup="xbrli:item" type="xbrli:decimalItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="osbc_CreditFacilityMember" name="CreditFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_DebtInstrumentMaturityTerm" name="DebtInstrumentMaturityTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_ThresholdForDisclosurePercentageOfStockholdersEquity" name="ThresholdForDisclosurePercentageOfStockholdersEquity" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets" name="FederalHomeLoanBankAdvancesAsPercentageOfTotalAssets" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="osbc_CapitalToRiskBasedRatiosAbstract" name="CapitalToRiskBasedRatiosAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_DividendRestrictionsAndDeferralsAbstract" name="DividendRestrictionsAndDeferralsAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_DividendRestrictionsNumberOfPreviousYearsRetainedProfit" name="DividendRestrictionsNumberOfPreviousYearsRetainedProfit" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_ClassOfWarrantOrRightTerm" name="ClassOfWarrantOrRightTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_NumberOfFinancialInstitutionsInvestmentSecuritiesPledged" name="NumberOfFinancialInstitutionsInvestmentSecuritiesPledged" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <element id="osbc_CommitmentsToExtendCreditToBorrowersMember" name="CommitmentsToExtendCreditToBorrowersMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="true" id="osbc_CommitmentsToExtendCreditNonborrowersMember" name="CommitmentsToExtendCreditNonborrowersMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_OldSecondCapitalTrustIMember" name="OldSecondCapitalTrustIMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_TrustPreferredSecuritiesIssuanceCostAmortizationPeriod" name="TrustPreferredSecuritiesIssuanceCostAmortizationPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <element id="osbc_TrustPreferredSecuritiesMaturityPeriod" name="TrustPreferredSecuritiesMaturityPeriod" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element id="osbc_InterestPaymentDefermentPeriod" name="InterestPaymentDefermentPeriod" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_TrustPreferredSecuritiesCashDistributionRatePercentage" name="TrustPreferredSecuritiesCashDistributionRatePercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_TrustPreferredSecuritiesCashDistributionFixedRatePercentage" name="TrustPreferredSecuritiesCashDistributionFixedRatePercentage" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_TrustPreferredSecuritiesBasisSpreadOnVariableRate" name="TrustPreferredSecuritiesBasisSpreadOnVariableRate" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_TrustPreferredSecuritiesDescriptionOfVariableRateBasis" name="TrustPreferredSecuritiesDescriptionOfVariableRateBasis" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_OldSecondCapitalTrustIIMember" name="OldSecondCapitalTrustIIMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_OtherFinancingReceivableMember" name="OtherFinancingReceivableMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio" name="LoansAndLeasesReceivableAsPercentageOfAggregatePortfolio" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember" name="CommercialRealEstateOwnerOccupiedGeneralPurposeLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember" name="CommercialRealEstateOwnerOccupiedSpecialPurposeLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember" name="CommercialRealEstateNonOwnerOccupiedGeneralPurposeLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember" name="CommercialRealEstateNonOwnerOccupiedSpecialPurposeLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_CommercialRealEstateRetailPropertiesLoanMember" name="CommercialRealEstateRetailPropertiesLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_CommercialRealEstateFarmLoanMember" name="CommercialRealEstateFarmLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ConstructionRealEstateHomebuilderLoanMember" name="ConstructionRealEstateHomebuilderLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ConstructionRealEstateLandLoanMember" name="ConstructionRealEstateLandLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ConstructionRealEstateCommercialSpeculativeLoanMember" name="ConstructionRealEstateCommercialSpeculativeLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ConstructionRealEstateOtherReceivableMember" name="ConstructionRealEstateOtherReceivableMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ResidentialInvestorLoanMember" name="ResidentialInvestorLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ResidentialOwnerOccupiedLoanMember" name="ResidentialOwnerOccupiedLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ResidentialRevolvingAndJuniorLiensLoanMember" name="ResidentialRevolvingAndJuniorLiensLoanMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ImpairedFinancingReceivableRelatedAllowanceAbstract" name="ImpairedFinancingReceivableRelatedAllowanceAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_HomeAffordableModificationProgramMember" name="HomeAffordableModificationProgramMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_FinancingReceivableModificationsSubsequentPaymentDefaultAbstract" name="FinancingReceivableModificationsSubsequentPaymentDefaultAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_RestrictedStockAndRestrictedStockUnitsMember" name="RestrictedStockAndRestrictedStockUnitsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationTerm" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardExpirationTerm" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsWeightedAverageRemainingContractualTermAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateIntrinsicValueAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock" name="ScheduleOfFairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_MortgageServicingRightsMember" name="MortgageServicingRightsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" name="FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisUnobservableInputReconciliationLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ScheduleOfEarningsPerShareBasicAndDilutedTable" name="ScheduleOfEarningsPerShareBasicAndDilutedTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_EarningsPerShareBasicAndDilutedLineItems" name="EarningsPerShareBasicAndDilutedLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_SeniorDebtFacilityMember" name="SeniorDebtFacilityMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossAbstract" name="FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetGainLossAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ImpairedLoansMember" name="ImpairedLoansMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_OtherRealEstateOwnedMember" name="OtherRealEstateOwnedMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <element id="osbc_ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses" name="ImpairedFinancingReceivableDecreaseOfSpecificAllocationsWithinProvisionForLoanLosses" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element id="osbc_RealEstateGross" name="RealEstateGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element id="osbc_ScheduleOfTroubledDebtRestructuringsOnFinancingReceivablesByTypeOfModificationTableTextBlock" name="ScheduleOfTroubledDebtRestructuringsOnFinancingReceivablesByTypeOfModificationTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_RealEstatePortfolioSegmentMember" name="RealEstatePortfolioSegmentMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element id="osbc_OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing" name="OutstandingLoanCommitmentsThresholdForCreditQualityCategorizing" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ScheduleOfPreferredStockTable" name="ScheduleOfPreferredStockTable" nillable="true" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_PreferredStockLineItems" name="PreferredStockLineItems" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_RealEstateCostOfRealEstateSoldNetOfGainLoss" name="RealEstateCostOfRealEstateSoldNetOfGainLoss" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element id="osbc_RealEstateAcquiredThroughForeclosureOperatingExpenses" name="RealEstateAcquiredThroughForeclosureOperatingExpenses" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <element id="osbc_InterestRateConcessionBelowNormalMarketMember" name="InterestRateConcessionBelowNormalMarketMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="true" id="osbc_OthersMember" name="OthersMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_DepositInterestPayableFairValueDisclosure" name="DepositInterestPayableFairValueDisclosure" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="osbc_RealEstateAcquiredThroughForeclosureRollForwardTableTextBlock" name="RealEstateAcquiredThroughForeclosureRollForwardTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <element id="osbc_AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract" name="AvailableForSaleSecuritiesDebtMaturitiesAmortizedCostWeightedAverageYieldAbstract" nillable="true" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="false" id="osbc_AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield" name="AvailableForSaleSecuritiesDebtMaturitiesWithinOneYearAmortizedCostWeightedAverageYield" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_ScheduleOfFinancingReceivablesToRelatedPartiesTableTextBlock" name="ScheduleOfFinancingReceivablesToRelatedPartiesTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_ScheduleOfComponentsOfDeferredIncomeTaxExpenseBenefitTableTextBlock" name="ScheduleOfComponentsOfDeferredIncomeTaxExpenseBenefitTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsDeferredCompensation" name="DeferredTaxAssetsTaxDeferredExpenseCompensationAndBenefitsDeferredCompensation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="false" id="osbc_DeferredTaxAssetsGoodwillAndIntangibleAssetsIntangibleAssets" name="DeferredTaxAssetsGoodwillAndIntangibleAssetsIntangibleAssets" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="false" id="osbc_DeferredTaxAssetsGoodwillAndIntangibleAssetsGoodwill" name="DeferredTaxAssetsGoodwillAndIntangibleAssetsGoodwill" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="false" id="osbc_DeferredTaxAssetsOtherRealEstateOwnedWriteDowns" name="DeferredTaxAssetsOtherRealEstateOwnedWriteDowns" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="false" id="osbc_DeferredTaxLiabilitiesStateTaxBenefits" name="DeferredTaxLiabilitiesStateTaxBenefits" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element abstract="false" id="osbc_DeferredTaxAssetsLiabilitiesGross" name="DeferredTaxAssetsLiabilitiesGross" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="true" id="osbc_ComponentsOfDeferredIncomeTaxExpenseBenefitAbstract" name="ComponentsOfDeferredIncomeTaxExpenseBenefitAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses" name="DeferredIncomeTaxExpenseBenefitProvisionForLoanLosses" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitDeferredCompensation" name="DeferredIncomeTaxExpenseBenefitDeferredCompensation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets" name="DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsIntangibleAssets" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <element id="osbc_DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost" name="DeferredIncomeTaxExpenseBenefitShareBasedCompensationCost" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns" name="DeferredIncomeTaxExpenseBenefitOtherRealEstateOwnedWriteDowns" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic" name="DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsDomestic" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal" name="DeferredIncomeTaxExpenseBenefitOperatingLossCarryforwardsStateAndLocal" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitDepreciation" name="DeferredIncomeTaxExpenseBenefitDepreciation" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitMortgageServicingRights" name="DeferredIncomeTaxExpenseBenefitMortgageServicingRights" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill" name="DeferredIncomeTaxExpenseBenefitGoodwillAndIntangibleAssetsGoodwill" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DeferredIncomeTaxExpenseBenefitOther" name="DeferredIncomeTaxExpenseBenefitOther" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock" name="FederalHomeLoanBankAndFederalReserveBankStockPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_TreasuryStockPolicyTextBlock" name="TreasuryStockPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_AlternativeMinimumMember" name="AlternativeMinimumMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_LifeInsuranceBankOwnedPolicyTextBlock" name="LifeInsuranceBankOwnedPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_ScheduleOfMaturitiesOfTimeDepositTableTextBlock" name="ScheduleOfMaturitiesOfTimeDepositTableTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_LongTermDebtByMaturityWeightedAverageInterestRateAbstract" name="LongTermDebtByMaturityWeightedAverageInterestRateAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths" name="DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInNextTwelveMonths" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo" name="LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateInYearTwo" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive" name="LongTermDebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRateAfterYearFive" nillable="true" substitutionGroup="xbrli:item" type="num:percentItemType" xbrli:periodType="duration" />
  <element id="osbc_DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate" name="DebtMaturitiesRepaymentsOfPrincipalWeightedAverageInterestRate" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="true" id="osbc_FixedLettersOfCreditMember" name="FixedLettersOfCreditMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_VariableLettersOfCreditMember" name="VariableLettersOfCreditMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_MortgageLoansServicingAssetAtFairValueAmount" name="MortgageLoansServicingAssetAtFairValueAmount" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="false" id="osbc_PeriodFromDueDateAfterWhichAccrualOfInterestIncomeIsDiscontinued" name="PeriodFromDueDateAfterWhichAccrualOfInterestIncomeIsDiscontinued" nillable="true" substitutionGroup="xbrli:item" type="xbrli:durationItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_ExpirationYear2025Member" name="ExpirationYear2025Member" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_FederalNationalMortgageAssociationMember" name="FederalNationalMortgageAssociationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_OperatingIncomeAbstract" name="OperatingIncomeAbstract" nillable="true" substitutionGroup="xbrli:item" type="xbrli:stringItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_OperatingIncome" name="OperatingIncome" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_FederalReserveBankRegulatoryReserveMember" name="FederalReserveBankRegulatoryReserveMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_MortgageBankingDerivativesMember" name="MortgageBankingDerivativesMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_OperatingLeasesLeaseRevenueExpenseNet" name="OperatingLeasesLeaseRevenueExpenseNet" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <element id="osbc_DeferredIncomeTaxExpenseBenefitStateTaxBenefits" name="DeferredIncomeTaxExpenseBenefitStateTaxBenefits" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="false" id="osbc_NoninterestBearingDepositsInBanks" name="NoninterestBearingDepositsInBanks" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="instant" />
  <xsd:element abstract="false" id="osbc_IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments" name="IncomeLossFromContinuingOperationsAfterIncomeTaxesBeforeMinorityInterestAndIncomeLossFromEquityMethodInvestments" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_DiscountedCashFlowValuationTechniqueMember" name="DiscountedCashFlowValuationTechniqueMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <element id="osbc_LoansAndLeasesReceivableDeferredIncomeExpenseNet" name="LoansAndLeasesReceivableDeferredIncomeExpenseNet" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="false" id="osbc_NonCashTransferOfLoansToOtherRealEstateOwned" name="NonCashTransferOfLoansToOtherRealEstateOwned" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="debit" xbrli:periodType="duration" />
  <xsd:element id="osbc_RealEstateOwnedParticipations" name="RealEstateOwnedParticipations" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="instant" />
  <xsd:element id="osbc_WealthManagementPolicyTextBlock" name="WealthManagementPolicyTextBlock" nillable="true" substitutionGroup="xbrli:item" type="nonnum:textBlockItemType" xbrli:periodType="duration" />
  <xsd:element id="osbc_NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity" name="NumberOfCustomersHavingSecuredBalancesExceedingSpecifiedPercentageOfStockholdersEquity" nillable="true" substitutionGroup="xbrli:item" type="xbrli:integerItemType" xbrli:periodType="instant" />
  <element id="osbc_RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment" name="RealEstateOwnedValuationAllowanceProvisionNetOfAdjustment" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="true" id="osbc_EmployeeAndNonemployeeStockOptionsMember" name="EmployeeAndNonemployeeStockOptionsMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <element id="osbc_ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock" name="ScheduleOfAvailableForSaleSecuritiesAndHeldToMaturitySecuritiesReconciliationTableTextBlock" nillable="true" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <xsd:element abstract="false" id="osbc_OtherComprehensiveIncomeAvailableForSaleSecuritiesUnrealizedHoldingGainLossNetReclassificationAdjustmentForAmountsRealizedAfterTax" name="OtherComprehensiveIncomeAvailableForSaleSecuritiesUnrealizedHoldingGainLossNetReclassificationAdjustmentForAmountsRealizedAfterTax" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_FederalHomeLoanMortgageCorporationMember" name="FederalHomeLoanMortgageCorporationMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <xsd:element abstract="false" id="osbc_AmountOfLoansHeldForSaleSold" name="AmountOfLoansHeldForSaleSold" nillable="true" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType" xbrli:balance="credit" xbrli:periodType="duration" />
  <xsd:element abstract="true" id="osbc_GCOEducationLoanFundingCorpMember" name="GCOEducationLoanFundingCorpMember" nillable="true" substitutionGroup="xbrli:item" type="nonnum:domainItemType" xbrli:periodType="duration" />
  <element id="osbc_RecaptureOfRestrictedStock" name="RecaptureOfRestrictedStock" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue" name="FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresCollateralPledgedSecuritiesFairValue" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_FederalHomeLoanBankAdvancesGeneralDebtObligations" name="FederalHomeLoanBankAdvancesGeneralDebtObligations" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_EquityIncentivePlan2014Member" name="EquityIncentivePlan2014Member" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DeferredTaxAssetsTaxCredit" name="DeferredTaxAssetsTaxCredit" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity" name="TransfersBetweenInvestmentsAvailableForSaleAndInvestmentsHeldToMaturity" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_ManagementAndAffiliatesMember" name="ManagementAndAffiliatesMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember" name="OldSecondBancorpIncEmployees401KSavingsPlanAndTrustMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TimeDeposits100000To250000" name="TimeDeposits100000To250000" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TimeDeposits250000OrMore" name="TimeDeposits250000OrMore" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_MortgageBackedAndCollateralizedMortgageObligationsMember" name="MortgageBackedAndCollateralizedMortgageObligationsMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DerivativeContractsExcludingMortgageBankingDerivativesMember" name="DerivativeContractsExcludingMortgageBankingDerivativesMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CapitalCommonAbstract" name="CapitalCommonAbstract" nillable="true" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneRiskBasedCapitalCommonEquity" name="TierOneRiskBasedCapitalCommonEquity" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CommonCapitalToRiskBasedRatiosAbstract" name="CommonCapitalToRiskBasedRatiosAbstract" nillable="true" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets" name="TierOneRiskBasedCapitalCommonEquityToRiskWeightedAssets" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy" name="TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacy" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized" name="TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalized" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" name="TierOneRiskBasedCommonCapitalRequiredForCapitalAdequacyToRiskWeightedAssets" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" name="TierOneRiskBasedCommonCapitalRequiredToBeWellCapitalizedToRiskWeightedAssets" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths" name="TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageNextTwelveMonths" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo" name="TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearTwo" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree" name="TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearThree" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter" name="TierOneCommonEquityCapitalDistributionLimitationMinimumRegulatoryCapitalPercentageYearFourAndThereafter" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_InterestPaidForBorrowings" name="InterestPaidForBorrowings" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate" name="GainLossOnDisposalOfFixedAssetsAndTransferOfPropertyToOtherRealEstate" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_AverageReserveBalanceWithReserveBank" name="AverageReserveBalanceWithReserveBank" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DividendsReceivedFromConsolidatedSubsidiaries" name="DividendsReceivedFromConsolidatedSubsidiaries" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_ScheduleOfAmortizedCostAndFairValueOfSecuritiesThatExceedTenPercentOfStockholdersEquityTableTextBlock" name="ScheduleOfAmortizedCostAndFairValueOfSecuritiesThatExceedTenPercentOfStockholdersEquityTableTextBlock" nillable="true" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_FederalFamilyEducationLoanProgramMember" name="FederalFamilyEducationLoanProgramMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_PercentageOfOutstandingPrincipalAmountOfLoansGuaranteedByUsDepartmentOfEducation" name="PercentageOfOutstandingPrincipalAmountOfLoansGuaranteedByUsDepartmentOfEducation" nillable="true" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DividendsDeclaredAndPaidPerShare" name="DividendsDeclaredAndPaidPerShare" nillable="true" type="num:perShareItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TalmerBancorpInc.Member" name="TalmerBancorpInc.Member" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNonInterestBearingDemandDeposits" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNonInterestBearingDemandDeposits" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestBearingSavingsNowMoneyMarketDeposits" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestBearingSavingsNowMoneyMarketDeposits" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedTimeDeposits" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedTimeDeposits" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_AmortizationOfSeniorNotesIssuanceCosts" name="AmortizationOfSeniorNotesIssuanceCosts" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_ProceedsFromIssuanceOfSeniorNotes" name="ProceedsFromIssuanceOfSeniorNotes" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TaxBenefitRealizedFromOptionExercises" name="TaxBenefitRealizedFromOptionExercises" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DebtInstrumentInterestRateTerm" name="DebtInstrumentInterestRateTerm" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_IncreaseInLoans" name="IncreaseInLoans" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans" name="NetDiscountAccretionOfPurchaseAccountingAdjustmentOnLoans" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_StockOptionPlan2009Member" name="StockOptionPlan2009Member" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome" name="IncomeTaxReconciliationNonDeductibleBankOwnedLifeInsuranceIncome" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_SummaryOfStockOptionActivityAbstract" name="SummaryOfStockOptionActivityAbstract" nillable="true" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedUnderAmendment" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorizedUnderAmendment" nillable="true" type="xbrli:sharesItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_InterestExpenseSenorNotes" name="InterestExpenseSenorNotes" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_InterestExpenseNotesPayableAndOtherBorrowings" name="InterestExpenseNotesPayableAndOtherBorrowings" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_ChangeInRestrictedStock" name="ChangeInRestrictedStock" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_MultiFamilyLoanMember" name="MultiFamilyLoanMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance" name="GainsLossesOnSalesOfOtherRealEstateBeforeProvisionForValuationAllowance" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TowdPointMortgageTrustMember" name="TowdPointMortgageTrustMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_ReimbursementRequestsGreaterThan5PercentMember" name="ReimbursementRequestsGreaterThan5PercentMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_ReimbursementRequestsGreaterThan9PercentMember" name="ReimbursementRequestsGreaterThan9PercentMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation" name="PercentOfInsuredLoansUsedAsBaseForLoansGuaranteedByUSDepartmentOfEducation" nillable="true" type="xbrli:pureItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment" name="DeferredTaxAssetsNetDeferredTaxExpenseValuationAdjustment" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment" name="DeferredIncomeTaxExpenseBenefitAfterDeferredTaxAssetValuationAdjustment" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CommercialPortfolioSegmentWithoutLeasesMember" name="CommercialPortfolioSegmentWithoutLeasesMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_LeasesComponentOfCommercialPortfolioSegmentMember" name="LeasesComponentOfCommercialPortfolioSegmentMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_GreaterChicagoFinancialCorpMember" name="GreaterChicagoFinancialCorpMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_FederalHomeLoanBankAdvancesAt142PercentageMember" name="FederalHomeLoanBankAdvancesAt142PercentageMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_FederalHomeLoanBankAdvancesAt144PercentageMember" name="FederalHomeLoanBankAdvancesAt144PercentageMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_AccumulatedOtherComprehensiveIncomeLossBreakdownAbstract" name="AccumulatedOtherComprehensiveIncomeLossBreakdownAbstract" nillable="true" type="xbrli:stringItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefit" name="TaxCutsAndJobsActOf2017IncomeTaxExpenseBenefit" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_StudentMarketingAssociationMember" name="StudentMarketingAssociationMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss" name="TaxEffectOfAdjustmentsRelatedToOtherComprehensiveLoss" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TermOfDeferredFinancingCosts" name="TermOfDeferredFinancingCosts" nillable="true" type="xbrli:durationItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans" name="NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnLoans" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestBearingDepositsWithFinancialInstitutions" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedInterestBearingDepositsWithFinancialInstitutions" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsFederalFundsSold" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsFederalFundsSold" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsFHLBCStock" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsFHLBCStock" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOtherRealEstateOwned" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOtherRealEstateOwned" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsGoodwillAndCoreDepositIntangible" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsGoodwillAndCoreDepositIntangible" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesTotalDeposits" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesTotalDeposits" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesSecuritiesSoldUnderRepurchaseAgreements" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesSecuritiesSoldUnderRepurchaseAgreements" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOtherShortTermBorrowings" name="BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesOtherShortTermBorrowings" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsNotExpectedToBeCollectedAtAcquisition" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAcquiredDuringPeriodCashFlowsNotExpectedToBeCollectedAtAcquisition" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_SalariesAndEmployeeBenefitsMember" name="SalariesAndEmployeeBenefitsMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_InformationTechnologyAndOtherMember" name="InformationTechnologyAndOtherMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableDiscountTableTextBlock" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableDiscountTableTextBlock" nillable="true" type="nonnum:textBlockItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_LoansAndLeasesReceivableExcludingPCILoansNetOfDeferredIncome" name="LoansAndLeasesReceivableExcludingPCILoansNetOfDeferredIncome" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome" name="LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncome" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYield" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYieldAdditions" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYieldAdditions" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYieldAccretion" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYieldAccretion" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYieldTransfersToLoansHeldForSale" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesNonAccretableYieldTransfersToLoansHeldForSale" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYield" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYieldAdditions" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYieldAdditions" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYieldTransfersToLoansHeldForSale" name="CertainLoansAcquiredInTransferNotAccountedForAsDebtSecuritiesAccretableAndNonAccretableYieldTransfersToLoansHeldForSale" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_NumberOfBranchesOperated" name="NumberOfBranchesOperated" nillable="true" type="xbrli:integerItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_OsbcAffiliatesMember" name="OsbcAffiliatesMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_CommercialLoanCustomersMember" name="CommercialLoanCustomersMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_InterestRateLockCommitmentsAndForwardContractsMember" name="InterestRateLockCommitmentsAndForwardContractsMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_LeaseRevenueForOtherRealEstate" name="LeaseRevenueForOtherRealEstate" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect" name="TaxCutsAndJobsActOf2017ReclassificationFromAociToRetainedEarningsTaxEffect" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo" name="DefinedContributionPlanEmployerMatchingContributionPercentOfMatchTwo" nillable="true" type="num:percentItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_OperatingLeasesFutureMinimumPaymentsDueInSixYears" name="OperatingLeasesFutureMinimumPaymentsDueInSixYears" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DeferredTaxAssetsBusinessCombinationAdjustments" name="DeferredTaxAssetsBusinessCombinationAdjustments" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DeferredTaxLiabilitiesIntangibleAssetsAmortization" name="DeferredTaxLiabilitiesIntangibleAssetsAmortization" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments" name="DeferredIncomeTaxExpenseBenefitBusinessCombinationAdjustments" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_ConstructionRealEstatePortfolioSegmentMember" name="ConstructionRealEstatePortfolioSegmentMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow" name="DepositsSavingsMoneyMarketDepositsAndNegotiableOrderOfWithdrawalNow" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings" name="NetPremiumAmortizationDiscountAccretionOfPurchaseAccountingAdjustmentsOnNotesPayableAndOtherBorrowings" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="duration" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_LoansAndLeasesReveivableAllowanceUnallocatedPortion" name="LoansAndLeasesReveivableAllowanceUnallocatedPortion" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="credit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue" name="LoansAndLeasesReceivableIncludingPurchasedCreditImpairedLoansNetOfDeferredIncomePastDue" nillable="true" type="xbrli:monetaryItemType" substitutionGroup="xbrli:item" xbrli:periodType="instant" xbrli:balance="debit" xmlns="http://www.w3.org/2001/XMLSchema" />
  <element id="osbc_MortgageServicingMember" name="MortgageServicingMember" nillable="true" type="nonnum:domainItemType" substitutionGroup="xbrli:item" abstract="true" xbrli:periodType="duration" xmlns="http://www.w3.org/2001/XMLSchema" />
</xsd:schema>
