Photocatalytic anaerobic organic oxidation coupled with H₂ evolution represents an advanced solar energy utilization strategy for the coproduction of clean fuel and fine chemicals. To achieve a high conversion efficiency, the smart design of efficient catalysts by the right combination of semiconductor light harvesters and cocatalyst is highly required. Herein, we report a composite photocatalyst composed of noble metal-free transition metal nitride Ni₃FeN decorated on 2D ultrathin ZnIn₂S₄ (ZIS) nanosheets for selective oxidation of aromatic alcohols to aldehydes pairing with H₂ production. In the composite, ultrathin ZIS serves as a light harvester that greatly shortens the diffusion length of photogenerated charges, while the metallic nitride Ni₃FeN acts as an advanced cocatalyst which not only captures the photoelectrons generated from the ultrathin ZIS to promote the charge separation, but also provides active sites to lower the overpotential and accelerate the H₂ reduction. The best photocatalytic performance is found on ZIS/1.5% M-Ni₃FeN, which shows a H₂ generation rate of 2427.9 μmol g^-1 h⁻¹ and a benzaldehyde (BAD) production rate of 2460 μmol g^-1 h^-1, about 7.8-fold as high as that of bare ZIS. This work is anticipated to endorse the exploration of transition metal nitrides as high-performance cocatalysts to promote the coupled photocatalytic organic transformation and H₂ production.