To prepare thermally stable and high-performance polymeric films, new solvent-soluble aromatic polyamides with a carbamoyl pendant group, namely poly(4,4'-diamino-3'-carbamoylbenzanilide terephthalamide) (p-PDCBTA) and poly(4,4'-diamino3'-carbamoylbenzanilide isophthalamide) (m-PDCBTA), were synthesized. The polymers were cyclized at around 200 to 350 degrees C to form quinazolone and benzoxazinone units along the polymer backbone. The decomposition onset temperatures of the cyclized m- and p-PDCBTAs were 457 and 524 degrees C, respectively, lower than that of poly(p-phenylene terephthalamide) (566 degrees C). For the p-PDCBTA film drawn by 40% and heat-treated, the tensile strength and Young's modulus were 421 MPa and 16.4 GPa, respectively. The film cyclized at 350 degrees C showed a storage modulus (E') of 1 x 10(11) dyne/cm(2) (10 GPa) over the temperature range of room temperature to 400 degrees C.