Potentially tetradentate ligands N,N′-di(2-hydroxybenzyl)ethylenediamine (L1) and N,N′-di(2-hydroxybenzyl)o-phenylenediamine (L2) and complexes of Cu(II), Co(II), and Ni(II) with L1 and L2 were synthesized. The EPR and electronic spectroscopy methods were used to reveal the octahedral structure of the Cu(II) complex with L1 in the solid state. In water-alcohol solutions, the Cu(II) and Ni(II) complexes with both ligands have distorted octahedral structures. The Co(II) complexes form dioxygen adduct with L1. In the presence of oxygen, the ligands in the obtained complex compounds can undergo oxidative dehydrogenation with selective formation of the respective disalicylaldimines. In the case of L2, the oxidative dehydrogenation is observed for the complexes of all studied metals in comparatively mild conditions (T = 30°C, methanol and other solvents), while in the case of L1, it occurs only with the Co(II) complexes in the presence of pyridine. © 2001 MAIK "Nauka/Interperiodica".