<SEC-DOCUMENT>0001209191-21-018574.txt : 20210308
<SEC-HEADER>0001209191-21-018574.hdr.sgml : 20210308
<ACCEPTANCE-DATETIME>20210308164128
ACCESSION NUMBER:		0001209191-21-018574
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20210306
FILED AS OF DATE:		20210308
DATE AS OF CHANGE:		20210308

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Partin Mark
		CENTRAL INDEX KEY:			0001688366

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37924
		FILM NUMBER:		21722495

	MAIL ADDRESS:	
		STREET 1:		21300 VICTORY BLVD.
		STREET 2:		12TH FLOOR
		CITY:			WOODLAND HILLS
		STATE:			CA
		ZIP:			91367

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			BLACKLINE, INC.
		CENTRAL INDEX KEY:			0001666134
		STANDARD INDUSTRIAL CLASSIFICATION:	SERVICES-PREPACKAGED SOFTWARE [7372]
		IRS NUMBER:				463354276
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		21300 VICTORY BOULEVARD
		STREET 2:		12TH FLOOR
		CITY:			WOODLAND HILLS
		STATE:			CA
		ZIP:			91367
		BUSINESS PHONE:		818-223-9008

	MAIL ADDRESS:	
		STREET 1:		21300 VICTORY BOULEVARD
		STREET 2:		12TH FLOOR
		CITY:			WOODLAND HILLS
		STATE:			CA
		ZIP:			91367
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2021-03-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001666134</issuerCik>
        <issuerName>BLACKLINE, INC.</issuerName>
        <issuerTradingSymbol>BL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001688366</rptOwnerCik>
            <rptOwnerName>Partin Mark</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>21300 VICTORY BLVD</rptOwnerStreet1>
            <rptOwnerStreet2>12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>WOODLAND HILLS</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>91367</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2021-03-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>11230</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>105910</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>111.53</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2021-03-06</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>24470</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2031-03-06</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>24470</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>24470</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each share is represented by a Restricted Stock Unit (&quot;RSU&quot;).  25% of the RSUs will vest on the one (1) year anniversary of February 20, 2021 (the &quot;Annual RSU Vesting Commencement Date&quot;), and 1/16th of the RSUs will vest every three months thereafter on the same day of the month as the Annual RSU Vesting Commencement Date, subject to the Reporting Person's continued service through each applicable vesting date.</footnote>
        <footnote id="F2">25% of the shares subject to the option will vest on the one (1) year anniversary of February 20, 2021 (the &quot;Annual Option Vesting Commencement Date&quot;), and 1/16th of the remaining shares subject to the option will vest every three months thereafter on the same day of the month as the Annual Option Vesting Commencement Date, subject to the Reporting Person's continued service through each applicable vesting date.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Karole Morgan-Prager, Attorney-in-Fact</signatureName>
        <signatureDate>2021-03-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
