We have developed the concept of photoactivation and elucidated the mechanism(s) of anti-cancer activity of photoactivated compounds. According to our model, light exposure results in the breakdown of the parent compound to yield potentially useful and novel small compounds. Using this modality, we have isolated and purified three new anti-cancer agents, the anti-tumor activities of which have been reported in our recent communications. These compounds are also being used as model for investigating apoptotic pathway in tumor cells.