Mnganese(II) hydrazone complexes derived from condensation of oxaloyldihydrazide with salicyaldehyde and ohydroxyacetophenone have been synthesized and characterized. The mode of bonding as well as the structure of the isolated compounds have been ascertained on the basis of data obtained from elemental analyses, spectral (UV-Vis., IR, mass, 1H NMR), magnetism and thermal (TG and DTA) measurements. The dihydrazones hesitate in their coordination to the metal center in between pentadentate to tetradentate manner forming mononuclear (octahedral) and binuclear (tetrahedral) complexes, respectively. Optical transmission spectra were recorded in the range 190– 2100 nm and some optical parameters such as band gap and refractive index have been determined. The inhibitive properties of all ligands for the corrosion of aluminum in 1 M HCl solutions were investigated using weight loss technique. The results pointed out that the two investigated ligands have reasonable inhibitions towards the corrosion of aluminum in acidic medium. The adsorption of the inhibitors on metal surface was found to be spontaneous first order reaction.