Photo-to-chemical　energy　conversion　requires　a　systematic　and　complex　molecular　design　to　manage　consecutive　photochemical　processes,　including　energy　harvesting,　exciton　migration,　electron　transfer,　charge　separation,　and　charge　transport.　However,　such　an　integrated　design　remains　a　substantial　challenge.　Here,　we　report　a　seamless　system　in　managing　these　photochemical　events　on　the　basis　of　two-dimensional　sp2　carbon-conjugated　covalent　organic　frameworks.　The　frameworks　are　designed　to　be　fully　π　conjugated　for　harvesting　a　wide　range　of　visible　to　near-infrared　light　and　to　constitute　built-in　donor-acceptor　heterojunction　interfaces　for　splitting　excitons.　The　frameworks　create　dense　yet　ordered　columnar　π　arrays　that　offer　pathways　to　facilitate　exciton　migration　and　charge　transport.　Loading　reaction　centers　in　pores　or　on　surface　shortens　the　electron-transfer　distance　and　promotes　the　accumulation　of　electrons　at　the　reaction　centers.　These　three　molecular　mechanisms　are　seamlessly　integrated　in　the　frameworks　and　render　the　system　able　to　efficiently　produce　hydrogen　that　is　driven　by　low-energy　photons.　Water　is　a　sustainable　energy　resource　on　this　planet.　Using　another　sustainable　energy　resource,　i.e.,　sunlight　to　decompose　water　into　hydrogen,　a　fuel　that　is　green　to　our　environment　and　society,　is　attracting　great　scientific　interest　and　public　concern.　However,　this　conversion　never　happens　spontaneously,　and　it　requires　a　complex　system　that　allows　a　flow　of　electrons　from　light　into　water.　To　realize　this　function,　this　work　creates　a　purely　organic　yet　robust　material　in　which　carbon-based　building　blocks　are　connected　with　a　specific　bond　in　a　topologically　pre-designable　ordered　manner.　This　unique　structure　not　only　collects　sunlight　efficiently　but　also　injects　electrons　to　water　through　a　built-in　interface,　enabling　an　immediate　yet　continuous　stable　hydrogen　production　from　water　upon　irradiation.　We　anticipate　that　this　work　will　offer　the　structural　and　mechanistic　base　for　scalable　and　sustainable　fuel　production　from　water　and　sunlight.　This　work　demonstrates　a　platform　for　designing　a　photocatalyst　to　promote　light-driven　production　of　hydrogen　from　water.　The　newly　developed　photocatalyst　consists　of　all　sp2　carbon　frameworks　that　are　fully　π　conjugated　to　promote　exciton　migration　and　offer　a　narrow　band　gap　to　harvest　visible　and　near-infrared　light.　Engineering　the　lattice　periphery　with　electron-deficient　units　tunes　the　band　structure　and　constitutes　built-in　interfaces　to　generate　electrons.　The　resulting　frameworks　enable　efficient,　continuous,　and　stable　hydrogen　production　under　irradiation.　©　2019　Elsevier　Inc.