Polymeric　carbon　nitride　(PCN)　has　attracted　intensive　interest　as　sustainable,　metal-free　semiconductor　for　photoelectrochemical　(PEC)　water　splitting.　Charge　transfer　along　the　films　acts　as　the　main　concern　to　restrict　the　performance　due　to　the　amorphous　nature　of　polymer.　Herein,　gradient　concentration　of　cobalt　disulfide　(CoS2)　merged　in　PCN　films　was　realized　as　CSCN　photoanode　by　a　one-pot　synthesis.　Owing　to　the　unique　properties　of　CoS2,　namely　high　conductivity,　the　charge　transfer　of　the　CSCN　photoanode　was　promoted,　and　thus　the　performance　for　PEC　water　oxidation　was　improved.　The　optimal　photoanode　exhibited　a　photoanodic　current　of　200　μA　cm−2　at　1.23　V　versus　reversible　hydrogen　electrode　under　air　mass　1.5　global　(AM　1.5G)　illumination,　which　was　approximately　4　times　that　of　the　pristine　PCN　photoanode.　This　work　provides　a　new　design　of　metal-free　photoanodes　to　improve　the　performance　of　water　splitting.　©　2022　Wiley-VCH　GmbH.