NiS is deposited on the surface of hexagonal ZnIn2S4 via a hydrothermal method and the as‐obtained NiS/ZnIn2S4 nanocomposite shows superior activity for photocatalytic dehydrogenative coupling of amines to produce imines, with simultaneous generation of hydrogen under visible light. The superior performance over NiS/ZnIn2S4 for photocatalytic dehydrogenative coupling of benzylamine to produce N‐benzylidenebenzylamine can not only be ascribed to NiS, which acts as a cocatalyst to promote the charge transfer and hydrogen evolution, but also attributed to its strong adsorption toward benzylamine and its relatively weak adsorption toward the product, which is also proved by density functional theory calculations. This study not only provides an efficient, green, and cost‐effective strategy to produce imines, but also demonstrates that the adsorption of the photocatalyst toward the reactants and the products is an important issue that should be considered in a photocatalytic reaction.