Tetradentate Schiff abase ligands, which were derived from the condensation of phenylenediamine with salicylaldehyde [salpphenH(2): N, N'-p-phenylene-bis(salicyclideneimine)] or 3,5-di-tert-butyl-2-hydroxybenzaldehyde [(tBu)salpphenH(2): N, N'-p-phenylene-bis(3,5-di-tert-butylsalicylidene)] and their complexes of Cu(II), Mo(IV) and adduct of Su(IV) were synthesized and characterized by H-1-NMR, C-13-NMR, and IR spectroscopic methods, mp, elemental analysis, and magnetic susceptibility. According to these data probable structures were assigned to these complexes and adduct. These are of the formula [Cu((tBu)salpphen)](2) and [MoCl2(salpphen)](2), and Sn2Cl8((tBu)salpphen).2HNEt(3). {Cu((tBu)salphhen)](2) was prepared by the reaction of the metal salt with the (tBu)salpphenH(2) Schiff base ligand in EtOH. [MoCl2(salpphen)](2) was synthesized by reactions of [MoCl4(CH3CN)(2)] with the salpphenH(2) Schiff base ligand in THF. The Schiff base adduct Sn2Cl8((tBu)salpphen).2HNEt(3) was synthesized by the reaction of SnCl4 with the (tBu)SalpphenH(2) Schiff base ligand in the presence of NEt3 in toluene.