A novel organic semiconductor photocatalyst analogous to natural light-harvesting antenna complexes in photosynthetic organisms, disulfide (-S-S-) bridged C3N3 polymer, was designed and developed to generate hydrogen from water under visible light irradiation.It was found that the artificial conjugated polymer only shows high H2-producing activity from the half-reaction of water splitting, similar to some inorganic semiconductor photocatalysts.The efficiency of H2 production could be improved greatly by adding a cocatalyst or a sacrificial donor.The results represent a potential and prospective application of the organic semiconductor in solar energy conversion.