Abstract: The photochemistry of 3-(2, 2-diphenylcyclopropyl)-3-methyl-l, I-diphenyl-1-butene was investigated in order to ascertain the reactivity of a system having one T moiety and one cyclopropyl ring attached to a saturated carbon. Only the singlet excited state proved reactive. As photochemical products there were obtained 1, I-diphenylethylene, 2-methyl-1, l- diphenyl-I-propene, 1, I-diphenylbutadiene, 4-methyl-l, l-diphenyl-l, 3-pentadiene, and 3-( ...