The immense recent progress of polymerization technology facilitates the construction of porous and highly ordered frameworks with engineered band structures by using the earth-abundant light-weight elements . The high robustness and nontoxicity of conjugated polymers have rendered them compelling photocatalysts for water splitting . Some reviews have summarized the progress of developing various conjugated polymers of different dimensions for photocatalytic hydrogen evolution from aqueous solutions , falling into classes of conjugated microporous polymers covalent triazine-based frameworks , covalent organic frameworks (COFs) , and linear conjugated polymers . However, linear polymers usually suffer high binding energy of excitons because of the limited electron delocalization in the one-dimensional configuration. For three-dimensional (3D) bulk polymers, the generated hole/electron pairs need to travel a long distance in 3D space to reach the water molecules at the surface. During this process, hole/electron recombination occurs and the photocatalytic efficiency is significantly reduced.