The research included preparation of new Schiff base (L) by two steps: preparation of precursor [bis(2-formyl-6-methoxyphenyl) succinate] (P) by reacting (3-methoxy salicyl aldehyde) with (succinoyl dichloride) as first step then react the prepared precursor (P) with (ethanethioamide) to have the new Schiff base [bis(2-((ethane thioyl imino) methyl)-6-methoxy phenyl) succinate] (L) as second step. Characterized compounds based on Mass spectra, 1 H, 13CNMR (for ligand (L)), FT-IR and UV spectrum, melting point, molar conduct, %C, %H, and %N, the percentage of the metal in complexes %M, magnetic susceptibility, while study corrosion inhibition (mild steel) in acid solution by weight loss. These measurements proved that by (Oxygen, Nitrogen, and Sulfur) atoms in the ligand, the metal ions are coordinated in a tetradentate form, and the tetrahedral structure of these complexes is suggested. Based on the measurement of micro elemental analysis (CHNS), the molar ratio appeared (2:1) (M:L). The complexes of [M2(L)Cl2]Cl2 type, where M= Cobalt(ii), Nickel(ii), Copper(ii) and Zinc(ii). These products were determined aligned with two classes of bacterial; bacteria (G+ ) and (G- ). The antibacterial effect of the metal complexes is greater than that of the ligand (free), according to the results of the bacterial activity test for the compounds. Results of corrosion inhibition of (L) and their complexes were determined by method (weight loss) in (0.2M) hydrochloric acid solution for mild steel.