ABSTRACTAttempting to couple photochemical CO2reduction with N2fixation is usually difficult, because the reaction conditions for these two processes are typically incompatible. Here, we report that a light-driven biohybrid system can utilize abundant, atmospheric N2to produce electron donors via biological nitrogen fixation, to achieve effective photochemical CO2reduction. This biohybrid system is constructed by incorporating molecular cobalt-based photocatalysts into N2-fixing bacteria. It is found that N2-fixing bacteria can convert N2into reductive organic nitrogen and create a localized anaerobic environment, which allows the incorporated photocatalysts to continuously perform photocatalytic CO2reduction under aerobic conditions. Specifically, the light-driven biohybrid system displays a high formic acid production rate of over 1.41 × 10−14mol h−1cell−1under visible light irradiation, and the organic nitrogen content undergoes an over-3-fold increase within 48 hours. This work offers a useful strategy for coupling CO2conversion with N2fixation under mild and environmentally benign conditions.