The azo Schiff base (A.S.B) under study was synthesized by mixing Schiff base and 2-aminobenzoic acid, whereas, the used Schiff base was obtained from the refluxing of salicylaldehyde and 2-aminothiophenol. The azo Schiff base reacted with Co(II) ion giving a chelate. The synthesized azo Schiff base and its Co(II) chelate were subjected to several physiochemical techniques; such as, CHNS elemental analyses, molar conductivity, IR, electronic, 1HNMR and mass spectra. The used techniques showed the formation of 2:1[M:L]chelate and confirm the geometrical structures of the azo Schiff base and its Co(II) chelate. A square planar geometry was established for the chelate. The inhibition characteristics of azo dye on steel corrosion in hydrochloric acid media is investigated at 300C. The results showed a high protection efficiency (greater than 85%) for acid corrosion of steel at its low concentration (3×10-3M).