Vibrational analyses are presented for the phosphorescences in polycrystalline methylcyclohexane and fluorescences in polycrystalline cyclohexane of C 6H 5CN, C 6D 5CN, p-, m-, and o-DC 6H 4CN at 77°K. These are consistent with planar nonhexagonal ring triplet state and planar, slightly expanded ring excited singlet state geometries. Based on polarization measurements, the triplet state is assigned 3 A 1 orbital symmetry.