A mixed Ni(II) ionic complex of {[Ni(2,2′-bpy)3][Ni(2-cpida)(2,2′-bpy)]}(ClO4).3H2O (1) (2-H3cpida = N-(2-carboxyphenyl)iminodiacetic acid, 2,2′-bpy = 2,2′-bipyridyl) has been synthesized and characterized by infrared, ultraviolet and fluorescence spectroscopy, elemental and thermogravimetric analysis. The molecular structure of compound 1, as determined by single-crystal X-ray diffraction studies, showed all the three carboxylate groups are in monodendate mode. Compound 1 consists of a discrete mononuclear [Ni(2,2′-bpy)3]2+ cation, a [Ni(2-cpida)(2,2′-bpy)]− anion, a ClO@ anion and three lattice water molecules. The H-bonding interaction between three lattice water molecule forms a V-shaped trimer (H2O)3 which gives rise to a 1-D polymeric structure in the solid state. Graphical Abstract A mixed ionic complex of Ni(II) contains V-shaped water trimer (H2O)3 through inter molecular hydrogen bonding interactions.