The anticorrosion potency of Sabic mild steel (MS) in 0.5 M H₂SO₄ solution was enhanced by three synthetic non-ionic surfactants (NI Surf.) containing pyridine and pyrimidine derivatives. These compounds are safe, environmentally friendly, and harmless to human health. Chemical and electrochemical measurements were used to compute the corrosion parameters. The anticorrosion efficacy increases with increasing the concentration of NI Surf. and with lowering temperature, surface and interfacial tension, and critical micelle concentration. The effectiveness of anticorrosion is interpreted due to the spontaneous horizontal adsorption on the surface of MS by the existence of some active centers that facilitate the adsorption. The adsorption process obeys Temkin isotherm. Potentiodynamic polarization elucidated that the synthetic NI Surf. acted as mixed-type inhibitors. Some surface properties were determined and confirm the anticorrosive effect of these molecules. Quantum chemical parameters as reactivity descriptors were carried out. It should be noted that the results obtained from computational calculations of the specifications are in full agreement with the experimental observations. There is good compatibility between the anticorrosion efficiency obtained from various techniques and surface properties and quantum chemical calculation.