For the first time, the synthesis, characterization, and electrochemical assessment as corrosion inhibitor of steel API 5L X52 immersed in 0.5 M HCl of the molecule 2-bromo-6(2′,6′-dichlorophenyl) dihydrobenzo [4, 5] imidazo [1,2c] quinazoline, 2Br2′,6′diClDHBIQz is reported. To evaluate the corrosion inhibition efficiency, IE, of this synthesized compound the following were assessed: inhibitor concentration, temperature, hydrodynamic conditions and steel exposure time to the corrosive medium. At 25 °C, EIS indicated the IE increased to 92.7% having added 15 ppm (0.03 mM) concentration, remaining practically constant (91.9 ± 0.78) % in the whole electrode angular speeds range considered; IE values higher than 85%, were attained even after 280 h acid exposure in stagnant conditions. SEM and AFM images revealed the steel-protective capacity of 2Br2′,6′diClDHBIQz while XPS analysis proved its presence onto the steel surfaces. The theoretical results are in complete agreement with the experimental XPS analyses.