Increased complexities in applications involving curable materials virtually need new materials that can overcome the limitations of existing ones. Resins, the structure of which is based on bisphenol A backbone terminated with three membered N-heterocycles-aziridines-have been synthesized, and their thermal-curing performance in solution and solid state was evaluated by NMR and FT-IR spectroscopies, differential scanning calorimetry, and single lap shear strength test and compared with that of analogous epoxy resin (diglycidyl ether of bisphenol A; DGEBA). Results reveal that the chemical reactivity of the aziridine-based resins is fine-tunable by controlling the N-substituent of aziridine. These resins can undergo ring-opening polymerization in the presence of various curing agents under unprecedentedly mild conditions and show remarkably rapid curing rate, wide substrate scope, and excellent chemoselectivity as compared to the analogous epoxy resin. Our results demonstrate superb curing ability of aziridine, making it promising for applications in materials and polymer sciences.