Two new layered complexes with the formulas of {[Cu(H 2 O)(HL) 2 Cl](NO 3 )} n (1) and {[Cu(H 2 O) 2 (HL) 2 ](NO 3 ) 2 } n (2) were solvothermally synthesized by the reactions of the bulky conjugated 4Ј-(4-hydroxyphenyl)-4,2Ј:6Ј,4ЈЈ-terpyridine ligand (HL) with different Cu II salts, which were further used as photocatalysts to achieve hydrogen production from water splitting. Single-crystal structural analyses reveal that both complexes feature coplanar (4 4) layers

The substituent group effect on the photocatalytic hydrogen evolution activity for water splitting was observed over a series of five isostructural copper(ii)-based layered coordination polymer photocatalysts.