The quantum yield of singlet oxygen (1O2 (1Δg)) production (ΦΔ) in the oxygen quenching of photoexcited states for 1,2-dicyanonaphthalene (1,2-DCNN), 1,4-dicyanonaphthalene (1,4-DCNN) and 2,3-dicyanonaphthalene (2,3-DCNN) in cyclohexane, benzene, and acetonitrile was measured using a time-resolved thermal lens (TRTL) technique, in order to determine the efficiency of singlet oxygen (1Δg) production in the first excited singlet state (S1), (fΔS). The efficiencies of singlet oxygen (1Δg) production from the lowest triplet state (T1), (fΔT), were nearly unity for all DCNNs in all the solvents. The values of fΔS were fairly large for 1,2-DCNN (0.33–0.57) and 1,4-DCNN (0.33–0.66), but were close to zero for 2,3-DCNN. Rate constants for oxygen quenching in the S1 state (kqS) obtained for these compounds were significantly smaller than diffusion-controlled rate constants. The kinetics for processes leading to production and no production of singlet oxygen is discussed on the basis of the values of fΔS and kqS. The results obtained regarding phenanthrene (PH), 9-cyanophenanthrene (9-CNPH), pyrene (PY) and 1-cyanopyrene (1-CNPY) are also discussed.