The interaction and corrosion properties of three different 1,2,4-triazole precursors on mild steel in 1 M hydrochloric acid have become studied by polarization, EIS, Adsorption, Surface studies and computational calculations at 300 K. Polarization studies showed that these molecules act as mixed type inhibitors. As the electron density around the inhibitor molecule increases through substitution, the inhibition efficiency also increases. Quantum chemical approach used to calculate electronic properties of the molecule to ascertain the relation between inhibitive effect and molecular structure. Electrochemical and theoretical studies agree fairly well. The results showed that DBATD is a better inhibitor than BATD and ATD. (C) 2012 Elsevier B.V. All rights reserved.