This article describes the synthesis of 4, 6-dihydroxyisophthalohydrazide (DIH) and its characterization using ¹H-NMR spectroscopy and evaluate its inhibiting performance against the aggressive attack of HCl on low carbon steel (CS). Chemistry and electrochemistry tools were used to investigate the inhibitor's effectiveness. In line with the Langmuir adsorption model, the results showed that the DIH compound greatly reduces the disintegration rate of CS by the adsorption process. Tafel data and EIS results showed that, the compound has a mixed-type characteristic. Raising the DIH concentration from 50 to 300 ppm reduces the charge transfer (R_ct) of CS from 48.6 to 351.3 ohm cm² and decreasing the adsorbed double layer's capacitance from 108 × 10^-6 to 13 ×10^-6 F cm^-2, respectively. A dosage of 300 ppm is optimal for 86.2 % inhibition effectiveness. Calculations using Monte Carlo (MC) simulations showed that the synthesized compound adhered to the CS quite well. The SEM/AFM results confirmed the existence of a protective film on the CS specimen. The in-vitro data that appeared from the killing test by using Postgate B media against SRB bacteria revealed the ability of DIH compound to reduce the perforation of bacteria from10⁶ cells/ml to nil at dosage of 300 ppm. The molecular docking simulation confirmed the obtained results.