in which Co 2 O 2 } dimers are connected through the corner-sharing of CoO 5 N} octahedra and PO 3 C} tetrahedra, forming an inorganic double-layer. Introduction of a second ligand (1,4-bis(imidazol-1-ylmethyl)benzene, L) in the reaction system, compound [Co(hppa)(L) 0.5 (H 2 O)]·H 2 O ( 3) was obtained. In this structure, Co 2+ ions are bridged by O–P–O bridges into an inorganic layer and the