Bis(5-hy­droxy­isophthalato-κO (1))bis­[4-(pyridine-3-carboxamido-κN (3))pyridinium]copper(II) tetra­hydrate

In the title compound, [Cu(C(11)H(10)N(3)O)(2)(C(8)H(4)O(5))(2)]·4H(2)O, the Cu(II) ion, located on a crystallographic inversion center, is coordinated in a square-planar environment by two trans-O atoms belonging to two monodentate 5-hy­droxy­isophthalate (hip) dianions and two trans nicotinamide pyridyl N-donor atoms from monodentate protonated pendant N-(pyridin-4-yl)nicotinamide (4-pnaH) ligands. The protonated 4-pyridyl­amine groups engage in N—H(+)⋯O(−) hydrogen-bond donation to unligated hip O atoms to construct supra­molecular chain motifs parallel to [100]. Water mol­ecules of crystallization, situated between the chains, engage in O—H⋯O hydrogen bonding to form supra­molecular layers and the overall three-dimensional network structure.