The present study has investigated the functional effect of modifying a simple function (-NH2) that correspond to a heterocycle (Benzodiazepine), acquired through two similar reactions, on the inhibition of mild steel corrosion (m-steel) in hydrochloric medium (1.0 M HCl). [5-((2-aminobutoxy) methyl)-quinolin-8-ol (Q-2) and 7-chloro-2,2,4-trimethyl-2,3 dihydro-1H benzo[b][1,4]diazepin-1-yl)methyl)quinolin-8-ol (Q-1)] were synthesized by two environmentally friendly reactions and characterized using Proton nuclear magnetic resonance (1H NMR) and Carbon nuclear magnetic resonance (13C NMR) spectroscopy. The inhibitory action of both organic compounds was evaluated by numerous techniques that have been already described in the literature (electrochemical impedance spectroscopy (EIS) and Potentiodynamic Polarization (PDP)).The inhibition efficiency increased with the increasing inhibitor concentration to 92.8% and91.1 % for Q-1 and Q-2 respectively at 10-3 M. The submerged surface of steel has been identified by scanning electron microscopy coupled with Energy Dispersive X-Ray Spectroscopy (SEM/EDS), Infrared spectroscopy (FT-IR), atomic force microscopy (AFM) spectroscopy and Contact angle measurements (theta). The corrosive solutions after corrosion tests have been identified by UV-visible spectrometry (UV-vis) and Inductively Coupled Plasma Emission Spectroscopy analysis (ICP-OES). The experimental studies PDP and EIS were completed by the theoretical studies Density-functional theory (DFT) and Monte Carlo (MC) simulation). Experimental data have shown that the studied additives Q-1 and Q-2 are effective against the corrosion acid of m-steel. In addition, their adsorption onto steel surface follow Langmuir adsorption isotherm.