A new ligand2-((1E,3E)-3-(2-(5-phenyl-4H-1,2,4-triazol-3-yl)hydrazono)prop-1-en-1-yl) phenol and its complexes with Co(ІІ), Ni(ІІ), Cu(ІІ) ions were synthesized. The new ligand and its complexes have been characterization on the basis their spectra of H 1 NMR, mas, Fourier transform infrared (FTIR), as well as magnetic susceptibility, elemental analysis (CHN) and conductance measurements. Molecular geometries have been studied using the density functiona l theory (DFT) with B3LYP/6-31G ++(d,p) basis set. In addition, the frontier molecular orbitals were performed atB3LYP/6-31++G (d,p) level of theory. The program of Hyperchem 8 has been used for theoretical accounts using PM3 method to study the electrostatic potential that provided good information about the complexity site. From the result obtained we can suggest octahedral geometries for Co (ІІ) and tetrahedral geometry for Cu(ІІ) and Ni(ІІ). The antioxidant activity of ligand was evaluated by DPPH scavenger and the ligand was showed high antioxidant activity.