Nanocrystalline　Zn-doped　and　Cu-doped　In(OH)ySz　solid　solutions　were　synthesized　from　In(NO3)3,　thiourea,　and　M(NO3)2　(M　=　Zn　and　Cu)　in　an　aqueous　solution　of　ethylenediamine　via　a　facile　hydrothermal　method.　The　samples　were　characterized　by　X-ray　diffraction　(XRD),　UV-vis　diffuse　reflectance　spectra　(DRS),　and　X-ray　photoelectron　spectroscopy　(XPS).　Although　both　Zn-doped　and　Cu-doped　In(OH)ySz　solid　solutions　show　visible-light-driven　photocatalytic　activities　in　the　decomposition　of　acetone　and　typical　dye　like　RhB,　their　photocatalytic　performance　is　quite　different.　Cu-doped　In(OH)　ySz　solid　solution　can　only　decompose　acetone　and　RhB　to　intermediates,　but　cannot　mineralize　them.　On　the　contrary,　Zn-doped　In(OH)　ySz　solid　solution　can　mineralize　acetone　and　RhB　to　CO2　and　its　photocatalytic　activity　is　a　little　enhanced　compared　to　that　of　the　undoped　In(OH)ySz　solid　solution.　Density　functional　theory　(DPT)　calculations　on　Zn-doped　and　Cu-doped　In(OH)　ySz　solid　solutions　reveal　that　the　introduction　of　M2+　(M　=　Zn　and　Cu)　into　In(OH)ySz　solid　solution　influences　the　electronic　structure.　The　different　photocatalytic　performance　observed　on　Zn-doped　and　Cu-doped　In(OH)ySz　solid　solutions　can　be　well　explained　by　their　different　electronic　structures.　©　2008　American　Chemical　Society.