The synthesis and characterization of [Cu(3-Me-2-tpc)2(nia)2] (1), [Cu(5-Me-2-tpc)2(nia)2] (2), [Cu(2-tpc)2(nia)2] (3) and [Cu(5-Me-2-tpc)2(nia)2(H2O)] (4) (where 2-tpc is 2-thiophenecarboxylate, 3-Me-2-tpc is 3-methyl-2-thiophenecarboxylate, 5-Me-2-tpc is 5-methyl-2-thiophenecarboxylate and nia is nicotinamide) are reported. The complexes under study were characterized by electronic, IR, EPR spectroscopy, magnetic susceptibility over the temperature range and X-ray structure analysis. The coordination arrangement around each copper(II) atom is a distorted tetragonal bipyramidal. The discrepancies between two Cu–O axial bond distances increases in the order: 0Å (complex 1)<0.050Å (complex 3)<0.209Å (complex 2)<0.516Å (complex 4, Cu1)<0.746Å (complex 4, Cu2), indicating that in the same order a distortion of the respective tetragonal bipyramids increases. This is in a good agreement with the ligand field band position in their electronic spectra.The complex molecules of all compounds are connected through H-bonds into supramolecular chains or frameworks. Spectral and magnetic behaviours are discussed with regard to X-ray parameters. Small negative value of Weiss constants confirm an existence of a very weak antiferromagnetic interaction between Cu(II) magnetic center in the crystal lattice.The EPR parameters are typical for a tetragonal bipyramidal Cu(II) complexes. The gav values at r.t. are somewhat lower than those at 77K.