The　hydrothiolations　of　alkynes/alkenes　with　thiols　is　an　atom-economic　and　thus　attractive　method　for　the　constructions　of　C-S　bonds.　Here　Ir2S3/ZnIn2S4　nanocomposites　with　varied　Ir2S3　loadings　were　obtained　by　one-pot　solvothermal　method　from　ZnCl2,　InCl3　and　thioacetamide　with　IrCl3.　The　loading　of　Ir2S3　on　the　surface　of　ZnIn2S4　promoted　the　hydrothiolations　of　alkenes　and　alkynes,　with　an　optimum　performance　observed　over　0.5　mol%　Ir2S3/ZnIn2S4　nanocomposite.　Based　on　the　studies　on　the　performance　of　several　other　cocatalysts　(MoS2,　NiS　and　Pd)　loaded　ZnIn2S4　and　the　EIS　analyses,　it　was　proposed　that　the　superior　performance　over　Ir2S3/ZnIn2S4　nanocomposite　can　be　ascribed　to　an　improved　efficiency　on　the　photogeneration　of　the　thiyl　radicals　by　loading　Ir2S3　as　well　as　its　inactivity　for　photocatalytic　hydrogen　evolution,　a　side　reaction　in　the　light　initiated　hydrothiolation　reaction　over　ZnIn2S4.　This　study　not　only　demonstrates　an　efficient　and　green　strategy　to　synthesize　thiolated　products　under　visible　light　based　on　semiconductor　photocatalysis,　but　also　provides　some　guidances　for　the　design　and　development　of　photocatalytic　systems　for　light　induced　organic　syntheses.　©　2021　Dalian　Institute　of　Chemical　Physics,　the　Chinese　Academy　of　Sciences