The　photocatalytic　activity　of　protonated　ordered　mesoporous　carbon　nitride　(pom-CN)　was　significantly　improved　by　assembling　anionic　[Mo3S13](2-)　clusters　as　cocatalysts　onto　the　surface　and　channel　of　pom-CN　via　electrostatic　interactions.　This　work　demonstrates　the　feasibility　of　employing　solution　chemistry　to　assemble　co-catalysts　in　the　form　of　ionic　clusters　as　building　blocks　into　a　photosynthetic　architecture.