An　efficient　chemical　system　for　electron　generation　and　transfer　is　constructed　by　the　integration　of　an　electron　mediator　([Co(bpy)　3]2+;　bpy=2,2-bipyridine)　with　semiconductor　photocatalysts.　The　introduction　of　[Co(bpy)3]2+　remarkably　enhances　the　photocatalytic　activity　of　pristine　semiconductor　photocatalysts　for　heterogeneous　CO2　conversion;　this　is　attributable　to　the　acceleration　of　charge　separation.　Of　particular　interest　is　that　the　excellent　photocatalytic　activity　of　heterogeneous　catalysts　can　be　developed　as　a　universal　photocatalytic　CO2　reduction　system.　The　present　findings　clearly　demonstrate　that　the　integration　of　an　electron　mediator　with　semiconductors　is　a　feasible　process　for　the　design　and　development　of　efficient　photochemical　systems　for　CO2　conversion.　©　2014　WILEY-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim.