Efficient H 2 O 2 Photosynthesis With Valorization by X‐Packing NDI Cocrystal Catalyst

Solar‐driven photocatalytic H 2 O 2 synthesis offers a sustainable and green alternative to the energy‐intensive anthraquinone process. However, coordinated regulation of electron‐transfer (ET) and energy‐transfer (EnT) pathways for efficient H 2 O 2 production remains challenging. Organic charge‐transfer (CT) cocrystals, which reconfigure the energy‐level structure through new intermolecular electronic states, provide a promising avenue to overcome this limitation. Herein, we report a CT cocrystal photocatalyst, DPNDI‐Py, prepared by liquid‐assisted grinding (LAG) of N, N′‐bis(4‐pyridyl)‐1,4,5,8‐naphthalenediimide (DPNDI) and pyrene (Py). The cocrystal harbors an X‐packed donor‐acceptor arrangement, with a crossing angle of 52° between the long axes of DPNDI and Py. Spectroscopic measurements confirm strong intermolecular CT, and transient spectroscopy supports CT‐related excited‐state dynamics and the formation of long‐lived triplet states, while theoretical calculations indicate electronic structure favorable for intersystem crossing (ISC). Mechanistic studies indicate that both EnT and ET pathways are utilized in photocatalysis. Under LED irradiation in air, DPNDI‐Py delivers an average H 2 O 2 production rate of 18.47 ± 0.57 mmol g −1 h −1 coupled with an 83.7 ± 2.26% dehydroascorbic acid (DHA) yield from ascorbic acid (AA) oxidation. This work provides mechanistic insight into CT‐mediated photocatalysis, offering a design principle for organic photocatalysts.