The photolyses of indene and naphthalene with acrylonitrile have been studied, and the products characterized. Indene reacts with acrylonitrile when the hydrocarbon absorbs light, or when a triplet sensitizer (acetophenone) is absorbing. Photolysis under the former conditions in ethanol yields 2-(1-indenylpropionitrile)(70%), 2-(3-indenylpropionitrile)(10%), and 6-cyano-2, 3-benzobicyclo [3, 2, 0] hept-2-ene (20%). Base-catalyzed isomerizations ...