The crystal structure of the title compound, [Zn(2)(C(8)H(7)O(2))(4)(H(2)O)(2)]·[Zn(2)(C(8)H(7)O(2))(4)(C(6)H(6)N(2)O)(2)]·2H(2)O, consists of two kinds of dinuclear Zn(II) complexes (complex A and complex B) and uncoordinated water mol-ecules. In complex A, [Zn(2)(C(8)H(7)O(2))(4)(H(2)O)(2)], each Zn cation is chelated by a 4-methyl-benzoate (PMB) anion and coordinated by a water mol-ecule, and is further bridged by two PMB anions in a trigonal-bipyramidal geometry. In complex B, [Zn(2)(C(8)H(7)O(2))(4)(C(6)H(6)N(2)O)(2)], each Zn(II) cation is coordinated by a monodentate PMB anion and one nicotinamide (NA) ligand, and is further bridged by two PMB anions in a tetra-hedral geometry. Weak intra-mol-ecular π-π stacking between adjacent benzene rings is observed in complex B, the centroid-centroid distance being 3.710 (2) Å. Extensive O-H⋯O and N-H⋯O hydrogen bonding and weak C-H⋯O hydrogen bonding is present in the crystal structure. The crystal studied was a racemic twin; the minor twin component refined to 38%.