ABSTRACT Through a controlled esterification strategy, a novel itaconic acid‐based epoxy resin (EIA) with a well‐defined structure, high purity, and excellent curing reactivity was successfully synthesized and characterized. For the first time, this study systematically elucidates the effects of aromatic ring content, amine curing agent basicity, and curing agent type on the long‐term mechanical stability and chemical resistance of EIA. Among the curing systems investigated, the methyl hexahydro