A new amino-containing phthalonitrile derivative 4-(4-(3, 5-diaminobenzoyl) phenoxy) phthalonitrile (DAPN) was successfully synthesized. Its structure was identified by FT-IR and H-1-NMR. DAPN can be thermally polymerized by duration at 230 A degrees C for various times under a nitrogen atmosphere, even in the absence of curing additives. The thermal properties of the cured products were characterized by TGA and DSC. The 5 and 10% weight loss temperatures ranged from 442 to 446 and 504 to 505 A degrees C, respectively. Char yields (800 A degrees C) were in the range of 72.7-72.9%. DSC data showed that the melting peak of the cured products disappeared due to their thermal polymerization. The insolubility in concentrated sulfuric acid and FT-IR of the cured products indicated the formation of cross-linked networks.