<p>Getting through the long tunnel leading to the next stage of artificial photosynthesis by molecular catalyst, an alternative pathway to bypass the photon-flux density problem of the rarefied sunlight radiation as the bottleneck is introduced from a bioinspired viewpoint. Based on a deep insight into the established system of natural photosynthesis, one-photon-induced two-electron water oxidation forming H₂O₂ by molecular catalyst could be one of the most promising electron sources for artificial photosynthesis. Earth abundant metalloporphyrins have realized water splitting into H₂/H₂O₂ as the first exemplum of artificial photosynthesis by visible light. The reductive fixation of CO₂ coupled with H₂O₂ formation has also been realized. The factors influencing the reactivity of the molecular catalyst-sensitized system (MCSS) have been unveiled, leading to continued investigation into preparing a transparent aqueous dispersion of monomeric semiconductor to serve as an electron relay in MCSS.</p> Graphical abstract <p></p>