Diaqua-bis[4-(dimethyl-amino)benzoato](isonicotinamide)zinc(II).

The mol-ecule of the title Zn(II) complex, [Zn(C(9)H(10)NO(2))(2)(C(6)H(6)N(2)O)(H(2)O)(2)], contains two 4-(dimethyl-amino)benzoate (DMAB) ligands, one isonicotinamide (INA) ligand and two water mol-ecules; one of the DMAB ions acts as a bidentate ligand while the other and INA are monodentate ligands. The four O atoms in the equatorial plane around the Zn atom form a distorted square-planar arrangement, while the distorted octa-hedral coordination is completed by the N atom of the INA ligand and the O atom of the water mol-ecule in the axial positions. Intra-molecular C-H⋯O hydrogen bonding results in the formation of a six-membered ring adopting an envelope conformation. The dihedral angle between the carboxyl groups and the adjacent benzene rings are 4.87 (16) and 2.2 (2)°, while the two benzene rings are oriented at a dihedral angle of 65.13 (8)°. The dihedral angle between the benzene and pyridine rings are 11.47 (7) and 74.83 (8)°, respectively. In the crystal structure, inter-molecular O-H⋯O, O-H⋯N and N-H⋯O hydrogen bonds link the mol-ecules into a supra-molecular structure. π-π contacts between the pyridine and benzene rings and between the benzene rings [centroid-centroid distances = 3.695 (1) and 3.841 (1) Å, respectively] further stabilize the structure. Weak inter-molecular C-H⋯π inter-actions are also present.