The reactions of fluoro-, chloro-, bromo-, and iodobenzenes with cyanomethyl anion in liquid ammonia havebeen studied with regard to the product distribution (1, 2-diphenylethane/phenylacetonitrile ratio). All the substratesgave about the same ratio. The addition of good electron acceptors such as naphthalene, anthracene, or pyridineinhibited the photostimulated reactions and gave a slight increase in the yield of 1, 2-diphenylethane. In reactionsstimulated by electrons the presence of naphthalene or benzoate ion as electron acceptors makes the yield of phenylacetonitrile drop almost to zero, whereas yields of the other products increase. Alternative reaction pathwaysare suggested. © 1979, American Chemical Society. All rights reserved.