Several new binuclear Cu-II, Ni-II, OVIV and Mn-II complexes of tridentate salicylaldimine (H2L), obtained from 3,5-di-t-butylsalicylaldehyde and o-aminophenol, have been prepared and characterized by analytical, spectroscopic (i.r., u.v.-vis., e.s.r.) techniques, magnetic and thermal measurements. The adduct formation or dissociation of these complexes in the presence of strongly coordinating solvents like pyridine and DMSO did not take place. The complexation of Co-II with H2L is accompanied by intramolecular electron transfer from the metal to the coordinated ligand yielding the radical ligand Co-III complex (g = 2.003, A(Co) = 10 G). The e.s.r. spectra of the Cu-II, OVIV and Mn-II complexes in the solid state and in solution are very broad due to intramolecular dipolar antiferromagnetic interactions.