Wholly aromatic polyamides were synthesized from the amidation reaction between unsymmetrical diamine containing a pyridyl ether linkage and aromatic dicarboxylic acid chloride. The resulting polyamides containing, pyridyl ether linkages showed high thermal stability (T-d5 =467 degrees C and enhanced solubility in organic solvents compared with the analogous polyamides having phenyl ether linkages. Substitution of just a single atom in a repeating unit was effective to disrupt the strong inter-chain interaction of parent aramid polymers. (c) 2005 Elsevier Ltd. All rights reserved.