AbstractNew epoxy‐imide resins were synthesized using bis(hydroxyphthalimide)s (BHPIs). Among these resins, that cured with BHPI(DDS), synthesized from 4,4′‐diaminodiphenylsulfone, exhibits the best thermal resistance, reaching a tan δ maximum temperature of 230°C. This resin also features a tensile lap shear adhesive strength of 320 kgf/cm2 when applied to steel test pieces. The cure reaction was followed by infrared spectroscopy and dynamic mechanical analysis. The ring‐opening reaction between the phenolic hydroxyl group of BHPI and the epoxy group is observed, and accelerated by a tertiary amine catalyst, triethylamine.