A series of new polyamides was synthesized by direct polycondensation of the 4,9-bis[4-(4-aminophenoxy)-phenyl]diamantane (I) with various dicarboxylic acids. The polyamides had high inherent viscosities and number-average molecular weights ((M) over bar(n)) of 0.65-1.65 dl g(-1) and 32000-140000, respectively. Although the symmetrical and rigid 4,9-diphenyldiamantane units were incorporated into polyamide III, especially, most polyamides III were extremely tough. Their elongation value at break was up to 60.5%. These films had tensile strength up to 116.1 MPa, and initial modulus reached 2.1 GPa. Two relaxations occurred on the temperature scale between 0 and 400 degrees C in these polyamides. Their oc relaxations arose at high temperatures, ranging from 342 to 381 degrees C. Moreover, these polyamides remained quite stable at high temperatures and maintained good mechanical properties (G＇approximate to ca. 10(8) Pa) up to temperatures close to the main transition markedly exceeding 330 degrees C. Furthermore, incorporating bulky diamantane units and the flexible ether linkages into the polyamides III, contributes toward the good solubility of most polyamides. In addition : their temperatures at a 5% weight loss ranged from 384 to 433 degrees C in air and from 387 to 436 degrees C in N-2 atmosphere.