Spectral, electrochemical and magnetic studies of mononuclear complexes CuL·nH₂O, Cu(L)A and binuclear complexes Cu₂L₂·nH₂O and Li(Cu₂L₂²A_–H) where L is a tridentate reduced Schiff base ligand and A is imidazole, reveal strong antiferromagnetic interactions in the binuclear complexes.