The inhibition of mild steel corrosion in 0.1 N nitric acid by the bis-1,2,4-triazole precursors EBATT and BBATT was investigated by potentiodynamic polarization (Tafel), electrochemical impedance spectroscopy (EIS), adsorption, and quantum chemical calculations at 300 K. Polarization studies showed that these molecules act as mixed-type inhibitors. As the electron density around the inhibitor molecules increases due to substitution, the inhibition efficiency also increases. The quantum chemical approach was also used to calculate electronic properties of the molecules to ascertain the correlation between inhibition effect and molecular structure. Experimental and theoretical studies agree well in this regard and confirm that BBATT is a better inhibitor than EBATT.