The use of supramolecular interactions (such as hydrogen bonding, etc. ) has become a major element in the quest for controlled supramolecular synthesis in the past few years. The unique strength and direction of hydrogen bonding plays a dominant role in the generation of variety of molecular architectures. Recently our research interest has been focused on syntheses and structural characterization of new dicarboxylato complexes of transitional metals, especially based on o-phthalic acid. In an extension of our studies here we present new Co(II) and Ni(II) complexes with terephthalic acid (H2tp) and 1-methylimidazole (1-MeIm), namely {[M(1-MeIm)2(H2O)4]·tp ·2H2O}, (M-Co(II) or Ni(II)), that has been characterized by crystal X-ray diffraction analyses, elemental analysis, IR spectroscopy and thermogravimetry. The crystal structure for both complexes consists of [M(1MeIm) 2(H2O)4]2+ cations and tp2- anions, and solvate water molecules. The uncoordinated oxygen atoms of the carboxylate groups of the terephthalate anion and solvate water molecules form a system of strong hydrogen bonds that give rise to 3D supramolecular networks.