Photoinduced energy transfer and electron transfer processes via the triplet state of 5,6-open-azaC 6 0 (2) were compared with those of 6,6-closed-azaC 6 0 (3) on the basis of kinetic data obtained by means of the transient absorption spectra. In nonpolar solvents such as toluene, energy transfer predominantly took place from the triplet states of 2 ( T 2 * ) and 3 ( T 3 * ) to retinol and β-carotene. The rate constant for energy transfer (k e n t ) from T 2 * to retinol was significant different from that of T 3 * . Furthermore, on the addition of methanol, the k e n t value of T 2 * for retinol was decreased, while no change was observed for that of T 3 * . These findings suggest that retinol is connected with T 2 * via the hydrogen-bond, but not with T 3 * . The decrease of the k e n t value of T 2 * by the addition of methanol suggests that retinol was replaced with methanol. In polar solvents such as benzonitrile, electron transfer took place from T 2 * / T 3 * ; however, the difference in the electron transfer rate between T 2 * and T 3 * was not observed for retinol. This finding implies that the hydrogen-bond between T 2 * and retinol was not formed in benzonitrile, since retinol was strongly solvated by the solvent molecules.