Abstract Several psoralen derivatives have been synthesized in order to evaluate their efficacy as photochemotherapeutic (PUVA) agents, including a variety of 4′-substituted-4, 5′, 8-trimethypsoralen compounds (1d-j). Improved synthesis of the very potent photosensitizers 8-methylpsoralen (6a) and 4, 8-dimethylpsoralen (6b) are described and 6a has been shown to undergo formylation in the 4′-position. Free radical bromination of ...