4-(((4-((5-Mercapto-1,3,4-oxadiazol-2-yl)methyl)-5-methylthiazol-2-yl)imino)methyl)benz ene-1,2-diol (5a) and 4- (((4-((5-Mercapto-1,3,4-oxadiazol-2-yl)methyl)-5-methylthiazol-2-yl)imino)methyl)-2,6-dimethoxyphenol (5b) are synthesized and their structures have been confirmed by IR and 1H-NMR spectral studies. Antioxidant activity of the synthesized compounds was investigated, and corrosion inhibition behaviour of the synthesized compounds on mild steel in 0.5 M HCl was studied by mass loss and electrochemical techniques. Thermodynamic adsorption parameters indicated both physisorption as well as chemisorption mechanism, and the process followed Langmuir adsorption isotherm. The polarization curves showed that both the compounds act as mixed type of inhibitor. FTIR spectra and scanning electron microscopy (SEM) were used to analyze the surface adsorbed film.