Photocatalytic two-electron oxygen reduction for hydrogen peroxide (H2O2) production represents a cost-effective and sustainable synthetic approach that has garnered significant attention. Inexpensive graphite-like carbon nitride (g-C3N4) features a tunable bandgap and impressive photocatalytic performance in the 2e- oxygen reduction reaction (ORR), facilitating H2O2 synthesis. This study presents the design of a defect vacancy ring-opening g-C3N4 that introduces specific C-OH sites at the edges of the ring openings. The g-C3N4 is covalently bonded to anthraquinone (AQ) via ester C-O-C=O oxygen bridges, resulting in a CN-O-AQ catalyst characterized by a silk-like, ordered stacked layer structure. The incorporation of specialized oxygen bridge bonds alters charge transport dynamics, establishing rapid charge diffusion pathways that enhance electron migration to the surface during the photoactivated oxygen reduction reaction. The synergistic effects of optimizing the (100) crystal plane crystallinity and introducing dual O/Cl element doping promote the development of new light absorption centers and lower oxygen adsorption energy while creating suitable electron vacancies. This combination significantly boosts the catalyst’s direct two-electron oxygen reduction capability for H2O2 formation. The CN-O-AQ catalyst achieved an impressive H2O2 yield of 626 mmol L-1, which is 14.9 times higher than that of pure CN (42 mmol L-1). This work elucidates the dual impact of modulating both crystal and electronic structures on photocatalytic performance, offering valuable insights for designing defect sites and doping strategies in organic conjugated structure catalysts.