1,3,4-Oxadiazole derivatives were prepared which have a number of therapeutic applications, and in a purpose of investigating the coordination behavior of new compounds towards transition metal ion, these compounds are prepared by oxidation of 5-aryl-1,3,4-oxadiazole-3-thiol using hydrogen peroxide forming bis(5-aryl-1,3,4-oxadiazole-2-yl) disulfide. The 1,3,4-oxadiazole compounds (LI, LII and LIII) have been used as ligands to prepared a number of transition metal complexes, which include [Fe(III), Co(II), Cu(II) and Mn(II)] ions. The ligands were characterized by F.T.IR spectroscopy, and their melting points. The metal complexes of the obtained ligands have been obtained in solid state and which are stable towards light, heat and moisture. They were characterized by F.T.IR, UV-Vis spectroscopy, conductivity, magnetic susceptibility measurements and metal analysis. On the basis of which techniques the structural formula of the complexes have been suggested which include: 1) The structural formula of Complexes of Fe(III), Co(II), Cu(II) and Mn(II) ions with (LI) as following : [Fe (LI)2(OH)2(SO4)2]2H2O, [Co (LI)2(H2O)2]Cl2 , [Cu (LI)2Cl2]C2H5OH , [Mn (LI)2(CH3COOH)2] H2O ,2) The structural formula of Complexes of Fe(III), Co(II), Cu(II) and Mn(II) ions with (LII) as following : [Fe2 LII(OH)2(H2O)2(SO4)2]H2O [Co LII(Cl)2(H2O)2]C2H5OH, [Cu (LII)2(H2O)2]Cl2 , [Mn LII(CH3COO)2(H2O)2]H2O, 3) The structural formula of Complexes of Fe(III), Co(II), Cu(II) and Mn(II) ions with (LIII) as following : [Fe2 LIII(H2O)6(SO4)2]H2O, [Co (LIII)2] H2O [Cu LIII(H2O)4]Cl2, [Mn2 LIII(H2O)8]2H2O, Different bonding and structural behavior were related during the study of coordination chemistry of the different new complexes. The Racah and other ligand field parameters which illustrate the bonding nature between metal ion and donor atoms of the ligand were calculated for Fe(III), Co(II) complex using (Tanabe-Sugano) diagram.