<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-02-01</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001289813</issuerCik>
        <issuerName>CRESCENDO ACQUISITION CORP.</issuerName>
        <issuerTradingSymbol>none</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001289813</rptOwnerCik>
            <rptOwnerName>CRESCENDO ACQUISITION CORP.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>RATIKONSTR. 33, POSTFACH 443</rptOwnerStreet1>
            <rptOwnerStreet2>SOFIGEN TREUUNTERNEHMEN REG.</rptOwnerStreet2>
            <rptOwnerCity>VADUZ, FURSTENTUM</rptOwnerCity>
            <rptOwnerState>N2</rptOwnerState>
            <rptOwnerZipCode>FL-9490</rptOwnerZipCode>
            <rptOwnerStateDescription>LIECHTENSTEIN</rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>William Tay former officer&amp;dir</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2006-02-01</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2006-02-01</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>11648000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0.0043</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">William Tay sold 11,648,000 shares of the common stock of Crescendo Acquisition Corp. to Industrial &amp; Family Holdings Ltd./W.I.P.  World International Project SA. Luxembourg of 16 Avenue de La Porte Neuve, BP 6661-2016 Luxembourg, on February 1, 2006 in a private transaction.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ William Tay</signatureName>
        <signatureDate>2006-02-02</signatureDate>
    </ownerSignature>
</ownershipDocument>
