Despite natural amino acids having been proposed as the green surrogate of currently used corrosion inhibitors that are generally toxic to both nature and human body during the everyday industrial processing of metallic equipments, their structural simplicity yet lowers the inhibitive potency, thereby hampering their further industrialization. We disclose here that a concise chemical ligation (Cu-I-catalyzed azide-alkyne 1,3-dipolar cycloaddition reaction [Cue-AAC]) between two L-amino acids that are weak or noncorrosion inhibitors may result in their largely improved protective effect for mild steel in HCl. A series of 1,4-disubstituted 1,2,3-triazolyl bis-amino acid derivatives constituted by L-serine, L-threonine, L-phenylalanine, and L-tyrosine were efficiently synthesized via Cue-AAC and deprotection reactions in high yields. Subsequently performed electrochemical impedance spectroscopy (EIS) evidenced that the inhibitive effect of these compounds for mild steel in 1 M HCl is markedly better than that of their natural amino acid counterparts. The inhibitive modality of the most potent inhibitor was interpreted in detail by potentiodynamic polarization and thermodynamic calculations. Furthermore, quantum chemical calculations suggest that the triazole ring formed by the Cue-AAC has contribution to their metal surface adsorption. This study would offer unique insights into the facile development of potency-enhanced green corrosion inhibitors based on the concise Cue-AAC ligation of natural amino acids.