Different　pathways　for　the　degradation　of　rhodamine　(RhB)　as　well　as　different　activity　order　for　the　degradation　of　RhB　and　methyl　orange　(MO)　were　observed　over　hexagonal　ZnIn2S4　microspheres　and　cubic　ZnIn2S4　nanoparticles.　A　detailed　study　of　the　physicochemical　and　surface　properties　of　these　two　ZnIn2S　4　polymorphs　has　been　carried　out　to　elucidate　these　phenomena.　The　results　reveal　that　hexagonal　ZnIn2S4　microspheres　are　composed　of　nanolamella　petals　growing　in　the　ab　plane,　i.e.,　the　negative　(0001)　S　plane.　This　negative　(0001)　S　plane　not　only　is　favorable　for　the　adsorption　of　the　cationic　dye　RhB　via　-N(Et)2　groups　but　also　can　accumulate　the　photogenerated　holes.　These　make　the　hole-directed　photocatalytic　de-ethylation　of　RhB　more　expedient　over　hexagonal　ZnIn2S　4　microspheres.　This　negative　(0001)　S　plane　of　hexagonal　ZnIn　2S4　microspheres　also　shows　promoting　effect　for　the　degradation　of　cationic　dye　like　MB,　but　not　for　the　degradation　of　anionic　dye　like　MO.　Our　result　provides　some　new　insights　in　how　the　surface　facet　can　take　effect　on　influencing　the　performance　of　a　photocatalyst　and　why　different　polymorphs　can　exhibit　different　photocatalytic　performance.　©　2012　American　Chemical　Society.