The enediynes 1 and 2 were photolyzed in 2-propanol to yield products akin to those analogous to a thermal Bergman cyclization mechanism. In addition, products resulting from photoreduction of one of the triple bonds of the enediyne functionality are also formed. The product distributions and yields were found to be dependent on the substituents on the triple bonds and on the nature of the double bond; in particular, phenyl substituents on the triple bonds eliminated the photoreduction products, and overall yields were higher when the double bond of the enediyne was of aromatic character. Triplet sensitization studies and laser flash photolysis experiments point toward radical mechanisms taking place during formation of both classes of products, with the photoreduction products forming from the excited triplet state and the cyclized naphthyl products forming from either the singlet or the triplet states. For the cyclization reaction, a substituted 1,4-dehydronaphthalene biradical species, structurally identical to a hypothetical Bergman biradical, is suggested to be the most likely intermediate.