The synthesis, structural spectroscopic properties of 4-(2-benzimidazolylazo)proline (BMP) and its complexes derived from [Cu(II), Ag(I) and Au(III)] salts were done. The mode of bonding for the complexes were accomplished based on elemental analysis, FTIR, UV-Vis and HNMR spectroscopy, magnetic measurement and molar conductivity. It has been found that the ligand (BMP) behaves as N,N-neutral bidentate which was forming chelates with molar ratio (1:2) (M:L) stoichiometry for [Cu(II) and Ag(I)] while Au(III) complex form molar ratio (1:1) at optimum concentration and pH as well as (l max ). The stability constant and Gibbs free energy for the prepared complexes are evaluated by spectroscopic methods. The prepared ligand (BMP) in comparison to its metal complexes, were screened for their antibacterial activity against two bacterial species, Escherichia coli and Staphylococcus. Dying performance was also studied.