A simple imide compound, 4-amino-phthalimide (APH), was synthesized as a curing agent for epoxy resin. APH was prepared from the hydration of 4-nitro-phthalimide, which was prepared from the nitration of phthalimide. The chemical structure of APH was verified by IR and H-1-NMR spectra. The thermal properties and dielectric constant (epsilon) of a phosphorus-containing novolac epoxy resin cured by APH were determined and compared with those of epoxy resins cured by either 4,4'-diamino diphenyl methane (DDM) or 4,4'-diamino diphenyl sulfone (DDS). The results indicate that the epoxy resin cured by APH showed better thermal stability and a lower epsilon than the polymer cured by either DDM or DDS. This was due to the introduction of the imide group of APH into the polymer structure. (C) 2008 Wiley Periodicals, Inc.