In the present study, five copper(II) complexes of quinoline-2-carbaldehyde benzoylhydrazone and a copper(II) complex of 2-benzoylpyridine benzoylhydrazone were synthesized. From the elemental analyses, conductivity measurements and by the determination of magnetic moments, the complexes were formulated. The complexes were characterized by IR, electronic and EPR spectroscopy. From the trend in g values, considerable covalent character is expected to the metal-ligand bonds and also, square pyramidal geometry is suggested for five coordinated complexes. Half field signals observed in the EPR spectra of [Cu(QCB)N-3](2)center dot H2O and [Cu-2(BPB)(2)(mu-SO4)], in solid state at 298 K and in frozen solution, confirm the dimeric structure for the complexes. The quantum chemical results obtained from the ab initio calculations for the aroylhydrazones and their Cu(II)- complexes were evaluated to explain the observed reactivity tendency of the compounds. (C) 2021 Elsevier B.V. All rights reserved.