Derivatives of 1,2,4 triazole ring especially those of 3-thionc show biological activities against different species of bacteria and fungi, therefore a new three mannich bases have been prepared, in an attempt to show the effect of introducing the amino methyl group in the triazole ring, as well as to investigate the coordination behavior of the new ligands toward transition metal ions and to compare the biological activity of the ligands and their complexes with the main ring structure. The new three ligands (L, L and L) were prepared by condensation of formaldehyde and appropriate amine (dipropyl amine, dibutyl amine and diisobutyl amine respectively) with (3-thione-4,5- diphenyll, 2,4-triazole) derivative in ethanol solution. the products were isolated and fully characterized by appropriate physical measurements, i.e., I.R and ¹H.N.M.R Spectroscopy as well as thermal analysis (TG-DTG). The new mannich bases (L, L and L) have been used as ligands to prepare a number of new complexes with the selected metal ions. The reaction of (L) with V(IV), Co(II), Cu(II) Zn(II), Pd(II) and Cd(II) ions exhibited the general formula: [l(M)m(L,)p(X)n].K(Solv.) The values of m, p, X, n and K varies with the type of the metal ion. While Rh(III) and Pt(IV) metal complexes exhibited a general formula: [(M)m(LOp(X)n].(X)n.K(Solv.) The values of m, p, X, X, n , n and K varies with the type of the metal ion. The complexes of Co(II), Zn(II) and Cd(II), were of tetrahedral geometry, while Pd(ll), Rh(III) and Cu(II) complexes gave square planer geometry, Pt(IV) gave an octahedral complex and that of V(IV) complex was square pyramidal. When (L,) interact with V(IV), Co(II), Cu(II), Zn(II), Pd(II) and Cd(II) ions, it gave complexes with the general formula: [M)m(L)p(X)n].K(Solv.) The values of m, p, X, n and K varies with the type of the metal ion. While Rh(III) and Pt(IV) complexes with the same ligand (L) exhibited a general formula: [(M)m(L)p(X)nl.(X)n.K(Solv.) The values of m, p, X, X, n , n and K varies with the type of the metal ion. The geometry of the Co(ll), Cu(ll), Zn(ll) and Cd(ll) complexes was tetrahedral and that of Pd(II), Pt(IV) and Rh(IIl) complexes was octahedral, while V(IV) complex had square pyramidal geometry. The ligand (Lm) react with V(IV), Co(II), Cu(II), Zn(II), Pd(II) and Cd(II) ions, to give complexes with the formula: [(M)m (L,,,)p (X),,]. K (Solv.) The values of m, p, X, n and K varies with the type of the metal ion. While Rh(III) and Pt(IV) complexes showed to have the formula of lRh(L)2l.Cl3 and Pt(L)2Cl2].Cl2. C2H5OH respectively. The Co(II), Cu(II), Zn(II) and Cd(II) complexes showed tetrahedral geometry, Pd(II) and Rh(III) square planer, Pt(lV) octahedral, while V(IV) complex gave square Pyramidal geometry. All the new prepared.metal complexes have been isolated, characterized and studied in solid state by studying their physicochcmical and analytical properties such as flame atomic absorption, I.R and UV-Vis. Spectra, conductivity and magnetic susceptibility measurements at room temperature, as well as thermal analyses (TG-DTG) A number of structural phenomena have been revealed during the study of the new mannich base complexes, also the Racah and other ligand field parameters have been calculated using the appropriate Tanaba-Sugano diagrams, in addition to that the degree of distortion of cobalt complexes have been calculated by using Spin-orbit coupling constant. The results helped to illustrate the bonding nature between metal ion and donor atoms of the ligands. The study of the nature of the complexes formed in ethanolic or chloroform solution following the mole ratio and continuous variation (Job's) methods, gave a results which were compared successfully with those obtained from solid stale studies. The apparent stability constant of the complexes have been studied with the time and showed that the colored complexes were stable, [Kstab. = (2.42* 105 - 9.21*109], this indicate that complexes of a mole ratio of M:L (1:2) or (2:1) exhibited a higher stability constants than complexes of mole ratio of (1:1), and their color were stable for more than (4) hours. The molar absorptivities were ranged from (2862-5511) L.mol-¹.cm-¹, this wide range indicate the great effect of the substituents on the nitrogen atom of aminomelhyl moiety in the structure of triazolc ring. The work also include a theoretical treatments of the formed complex in the gas phase, this was done using the hyperchem-6 program for the Molecular mechanics and Semi-empirical calculations. The heat of formation (ΔHf°) and binding energy (ΔEb) for all free ligands and their metal complexes were calculated by (PM3, ZINDO and AMBER) methods, at 298 °K. It was found that the ligand (L) and its' metal complexes were more stable than (L and L) and their metal complexes, this difference in stability sequence could be related to the difference in the types of the alkyl group of aminomethyl derivatives upon the structure of triazole, the results also indicate that complexes of M:L mole ratio of (1:2) or (2:1) were more stable than those with mole ratio of (1:1), which agreed well with the experimental stability constants in solution. Furthermore the electrostatic potential of the free ligands were calculated to investigate tile reactive sites of the molecules. PM3 was used to evaluate the vibration spectra of the free ligands (Ll L and L) and comparing the theoretically calculated wave numbers with the experimental values by using 3-thione-4,5-diphenyl-1,2,4- triazole as authentic compound. The theoretically obtained frequencies agreed well with those found experimentally in addition, the calculation helped to assign unambiguously the most diagnostic bands. The antibacterial activity for all ligands and their metal complexes were studied against two selected micro-organisms (E. coli) and (Staph. aureus), the minimal inhibitory concentration (MIC) have been also studied to determined the low concentration for inhibition, two antibiotics (Ampicillin and Amoxicillin) have been Chosen to compare their activity with those of the new compounds. The results showed higher activity of the new compounds relative to the chosen antibiotics. Furthermore the antifungal activity against two micro-organism (Panic. Spp and Asp. flaveus) were studied for all ligands and their metal complexes. The results showed great enhancement of the complexes relative to that of their respective ligands. This was attributed to the synergetic effect between the metal ion and the ligand, in addition to the differences in the structural varieties.