Abstract: Reaction parameters were optimized for the synthesis of high molecular weight omega-phenylalkyl-substituted derivatives of poly(p-xylylene) (PPX) by base-induced 1,6-dehydrohalogenation of corresponding 4-halogenomethyltoluenes. Class transition temperatures decreased systematically with increasing alkyl spacer of the lateral substituent. The highest elongation at break was observed for the 4-phenylbutyl-substituted PPX. Level I tests on the biocompatibility of 4-phenylbutyl-substituted PPX indicated low toxicity.