Two new imidazolium-based ionic liquids namely, 1-hexadecyl-3-(4-methylbenzyl)-1H-imidazol-3-ium chloride (IL-CH3), and 1-hexadecyl-3-(4-nitrobenzyl)-1H-imidazol-3-ium chloride (IL-NO2) were synthesized. The inhibitory activity of these compounds against the corrosion of low-carbon steel (LCS) in a 1 M HCl was examined by utilize multiple techniques such as polarization (PP) and electrochemical impedance spectroscopy (EIS). The outcome data displayed that the protection efficiency rises with improving the dose of IL'S (IL-CH3, IL-NO2). PP data confirm that they are mixed kind inhibitors. Best performances (i.e. 92.9% and 94.5%) were recorded at maximal IL-CH3 (100 ppm) and IL-NO2 (100 ppm) doses, respectively. These findings imply that the novel ionic liquids (IL-CH3, IL-NO2) are efficient corrosion inhibitors.