(2E)-2-(acetylamino)-3-(4-nitrophenyl)prop-2-enoic acid (NPP) was synthesized following a facile chemical method from 4-nitrobenzaldehyde (NB) and thoroughly characterized using spectroscopic techniques. These compounds were applied as novel inhibitors for corrosion of mild steel in 1M HCl using various methods such as absorbance difference, potentiodynamic polarization, and electrochemical impedance spectroscopy (EIS). The results indicate that these inhibitors show an excellent protection performance and achieve the corrosion inhibition efficiency values of 94% and 84% for NPP and NB, respectively. Theadsorption of these molecules obeys the El-Awady isotherm model. The surface analysis of mild steel was investigated using scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) methods. Furthermore, quantum chemical calculations were investigated using DFT method at B3LYP/6-31G (d,p)computed by Gaussian 09 showing a good correlation with the experimental results