A　metal–insulator–semiconductor　(MIS)　photosystem　based　on　covalent　organic　framework　(COF)　semiconductors　was　designed　for　robust　and　efficient　hydrogen　evolution　under　visible-light　irradiation.　A　maximal　H2　evolution　rate　of　8.42　mmol　h−1　g−1　and　a　turnover　frequency　of　789.5　h−1　were　achieved　by　using　a　MIS　photosystem　prepared　by　electrostatic　self-assembly　of　polyvinylpyrrolidone　(PVP)　insulator-capped　Pt　nanoparticles　(NPs)　with　the　hydrophilic　imine-linked　TP-COFs　having　=C=O−H−N=　hydrogen-bonding　groups.　The　hot　π-electrons　in　the　photoexcited　n-type　TP-COF　semiconductors　can　be　efficiently　extracted　and　tunneled　to　Pt　NPs　across　an　ultrathin　PVP　insulating　layer　to　reduce　protons　to　H2.　Compared　to　the　Schottky-type　counterparts,　the　COF-based　MIS　photosystems　give　a　32-fold-enhanced　carrier　efficiency,　attributed　to　the　combined　enhancement　of　photoexcitation　rate,　charge　separation,　and　oxidation　rate　of　holes　accumulated　in　the　valence　band　of　the　TP-COF　semiconductor.　©　2019　Wiley-VCH　Verlag　GmbH　&　Co.　KGaA,　Weinheim