The anti-corrosive properties of 2-aminomethylbenzimidazole (AMB) and bis(benzimidazol-2-ylethyl)sulfide (BBES) were analyzed by electrochemical techniques such as polarization curves and electrochemical impedance spectroscopy (EIS). The results show that AMB behaves as a cathodic inhibitor, while BBES functions as mixture inhibitor. Furthermore, BBES inhibits the corrosive process more strongly than AMB; because in the former benzimidazoles and thioether sulfur work as active sites for the adsorption process over the metal surfaces. This observation is supported by density functional theoretical (DFT) parameters such as frontier molecular orbitals (HOMO and LUMO), Mulliken charges and the electrostatic potential map. (C) 2005 Elsevier B.V. All rights reserved.