Self-crosslinkable poly (arylene ether)s 6 and 8, containing pendent triazene groups were prepared by nucleophilic substitution reaction of poly (arylene ether) s 5 and 7, respectively, with 1-[4-(4-hydroxyphenoxy) phenylene] triazenes, 4, in the presence of potassium carbonate in N,N-dimethylacetamide. A series of triazenes 4 containing various substituents have been synthesized. Self-crosslinkable polymer 6e containing phenyl-substituted triazene pendants can be crosslinked at 215-degrees-C, which is about 40-degrees-C lower than the glass transition temperature of the virgin base polymer 5. The degree of crosslinking can be tailored by varying the concentration of the pendent phenylenetriazene groups in the polymer. After curing, the flexible polymer films (ca. 10 mum thick) exhibit high gel contents, increased glass transition temperatures, improved resistance to organic solvents, and little change in dielectric constant and thermal stability. These self-crosslinkable poly (arylene ether) s are potential candidates for electronic applications.