Development of efficient molecular catalysts for photocatalytic CO2 reduction is desirable but challenging.At present,the majority of reported molecular catalysts consist of the transition metal centers coordinated by N-containing ligands.Inspired by the sulfur-containing active site found in carbon monoxide dehydrogenases,we here report a novel Ni-based molecular catalyst bearing 2,6-bis([(2-pyridinylmethyl)thio]methyl) pyridine) as the pentadentate ligand.The product is assessed for photocatalytic CO2 reduction in acetonitrile/water solution using Ru(bpy)3Cl2 as the photosensitizer and triethanolamine as the electron donor.Under the optimal condition,a total of ca.25 μmol CO is produced after 7 h visible light irradiation with a large turnover number of 63 and high selectivity of 91％.