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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2013-02-04</periodOfReport>

    <dateOfOriginalSubmission>2013-04-23</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001375200</issuerCik>
        <issuerName>NUPATHE INC.</issuerName>
        <issuerTradingSymbol>PATH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0000086115</rptOwnerCik>
            <rptOwnerName>SAFEGUARD SCIENTIFICS INC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>435 DEVON PARK DRIVE, BLDG. 800</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>WAYNE</rptOwnerCity>
            <rptOwnerState>PA</rptOwnerState>
            <rptOwnerZipCode>19087-1945</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2013-02-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>28011</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>3.57</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5160377</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by SDI</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares issued in connection with accrued dividends on the Series A Preferred Stock.</footnote>
    </footnotes>

    <remarks>The securities are indirectly owned by the reporting person and are directly owned by Safeguard Delaware, Inc. (&quot;SDI&quot;), a wholly owned subsidiary of the reporting person.  Safeguard may be deemed a director by virtue of the fact that employees of Safeguard serve on the Issuer's board in connection with their employment duties.</remarks>

    <ownerSignature>
        <signatureName>By: Brian J. Sisko EVP &amp; Managing Director  For: Safeguard Scientifics, Inc.</signatureName>
        <signatureDate>2013-04-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
