<?xml version="1.0" encoding="US-ASCII"?>  
<!-- Generated by CompSci Transform (tm) - http://www.compsciresources.com -->    
<!-- Created: Fri Jul 11 17:08:44 UTC 2025 -->  
<xs:schema elementFormDefault="qualified" xmlns:bxsl="http://www.bxsl.com/20250711" targetNamespace="http://www.bxsl.com/20250711" xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:us-types="http://fasb.org/us-types/2025" xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xmlns:dtr="http://www.xbrl.org/dtr/type/2024-01-31" xmlns:xbrli="http://www.xbrl.org/2003/instance"> 
  <xs:annotation>   
    <xs:appinfo>  
      <link:linkbaseRef xlink:type="simple" xlink:href="bxsl-20250711_lab.xml" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:role="http://www.xbrl.org/2003/role/labelLinkbaseRef"/> 
      <link:linkbaseRef xlink:type="simple" xlink:href="bxsl-20250711_pre.xml" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:role="http://www.xbrl.org/2003/role/presentationLinkbaseRef"/>   
      <link:linkbaseRef xlink:type="simple" xlink:href="bxsl-20250711_def.xml" xlink:arcrole="http://www.w3.org/1999/xlink/properties/linkbase" xlink:role="http://www.xbrl.org/2003/role/definitionLinkbaseRef"/> 
    </xs:appinfo>   
  </xs:annotation>    
  <xs:import namespace="http://www.xbrl.org/2003/instance" schemaLocation="http://www.xbrl.org/2003/xbrl-instance-2003-12-31.xsd"/>  
  <xs:import namespace="http://www.xbrl.org/2003/linkbase" schemaLocation="http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd"/>  
  <xs:import namespace="http://www.xbrl.org/2009/role/negated" schemaLocation="http://www.xbrl.org/lrr/role/negated-2009-12-16.xsd"/>    
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  <xs:import namespace="http://xbrl.sec.gov/cef/2025" schemaLocation="https://xbrl.sec.gov/cef/2025/cef-2025.xsd"/> 
  <xs:import namespace="http://xbrl.sec.gov/cef-pre/2025" schemaLocation="https://xbrl.sec.gov/cef/2025/cef-2025_pre.xsd"/>    
  <xs:import namespace="http://www.xbrl.org/dtr/type/2024-01-31" schemaLocation="https://www.xbrl.org/dtr/type/2024-01-31/types.xsd"/>     
  <xs:element name="RisksRelatedToOurBusinessAndStructureMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_RisksRelatedToOurBusinessAndStructureMember"/>   
  <xs:element name="RisksRelatedToOurInvestmentsMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_RisksRelatedToOurInvestmentsMember"/>     
  <xs:element name="RisksRelatedToTheAdvisersAndTheirAffiliatesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_RisksRelatedToTheAdvisersAndTheirAffiliatesMember"/>     
  <xs:element name="RisksRelatedToBusinessDevelopmentCompaniesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_RisksRelatedToBusinessDevelopmentCompaniesMember"/>   
  <xs:element name="RisksRelatedToDebtFinancingMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_RisksRelatedToDebtFinancingMember"/>   
  <xs:element name="FederalIncomeTaxRisksMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_FederalIncomeTaxRisksMember"/> 
  <xs:element name="RisksRelatedToAnInvestmentInTheCommonSharesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_RisksRelatedToAnInvestmentInTheCommonSharesMember"/>     
  <xs:element name="NetInvestmentIncomeMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_NetInvestmentIncomeMember"/>  
  <xs:element name="NetRealizedCapitalGainsMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_NetRealizedCapitalGainsMember"/>     
  <xs:element name="CommonSharesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_CommonSharesMember"/>   
  <xs:element name="PreferredSharesMember" type="dtr:domainItemType" abstract="true" xbrli:periodType="duration" nillable="true" substitutionGroup="xbrli:item" id="bxsl_PreferredSharesMember"/>    
</xs:schema>
