Reaction of O-3(2) with singlet excited state (S-1) of highly luminescent cycloparaphenylenes (CPPs), i.e., [n]CPP where n = 9, 12, and 15 in solution has been studied by transient absorption (TA) measurements seamless for the time range from subnanosecond to microsecond based on the randomly-interleaved pulse-train (RIPT) method recently developed by our group. We found efficient quenching of S-1 by O-3(2) through observation of S-n <- S-1 transient absorption and the steady state fluorescence measurements. Concomitantly, we have become aware of the acceleration of the rate of intersystem crossing (ISC) from S-1 to the triplet excited state (T-1) through the observation of the evident enhancement of T-n <- T-1 absorption intensity. We have established the analysis procedure to evaluate the rate constant of ISC (k(ISC)(0)) in the absence of O-2 and the bimolecular rate constant of ISC induced by O-3(2) (k(ISC)(O2)) only by using TA decay data in the presence of O-2. On the basis of these analyses, we further succeeded in determining the quantum yield of T-1 (Phi(T)) with and without O-2. In addition, the absorption coefficient of T-1 (epsilon(T1)) and S-1 (epsilon(S1)) could be estimated with reference to that of T-1 of C-60. These photophysical parameters are largely dependent on the ring size, where the lifetime of S-1 (tau(S)) in the absence and presence of O-2 dominates Phi(T) as well as the quantum yield of fluorescence (Phi(F)).