A number of novel styryl epoxides, N‐substituted‐styryl‐ethanolamines, N‐mono and N,N′‐bis‐(2‐hydroxyethyl)‐cinnamamides ‐ analogues to the known radiosensitizers RSU‐ 1069, pimonidazole and etanidazole ‐ display selective hypoxicradiosensitizing activity. The styryl group, especially when substituted by electron withdrawing groups, was found to be bioisosteric to the nitroimidazolyl functionality