Bis(di-5-Bromosalicylaldehyde)biphenyl-3,3'-dimethoxy-4,4'-diamine (H2L1) and its Co(II), Ni(II), Cu(II), and Zn(II) complexes have been synthesized and characterized by elemental analysis, magnetic moment, UV-Vis., IR, 1H NMR,13C NMR and ESR spectral techniques. Also, the thermal properties were examined by TGA. The corrosion inhibition of compounds has been investigated by weight loss, potentiodynamics polarization, and SOM on mild steel in (0.5M) HCl. The adsorption of compounds was founded to obey the Langmuir adsorption isotherm model and show mixed type inhibition behavior. The antibacterial activity of compounds was measured against SRB. The antibacterial results showed a good antibacterial activity of the synthesized compounds.