The dyad sequence analysis of Technora (copolyamide prepared from terephthaloyl chloride, p-phenylenediamine, and 3,4'-diaminodiphenyl ether) was reported using C-13 NMR in trifluoromethanesulfonic acid at 100 degreesC. For the detailed peak assignment, some model copolymers were synthesized and the C-13 NMR spectra were observed. Well-resolved carbonyl carbon peaks of the terephthalic units of Technora were observed, which made it possible to analyze the p-phenylenediamine units and the 3,4'diaminodiphenyl ether units at dyad level. The information on the head-to-head, tail-to-tail, and head-to-tail sequences of the 3,4'-diaminodiphenyl ether units was also obtained. It was concluded that the sequence of Technora was completely random.