The intersystem crossing rate (k isc) and excited state lifetime of asymmetric pentaazadentate porphyrin-like metal complexes, [(R-APPC)M]Cl n], were investigated. The time-correlated single photon counting (TCSPC) method was used to calculate the first singlet excited state lifetimes (τ s) of the sample complexes. It was observed that the values of the intersystem crossing rate and excited state life time of the sample complexes were sensitive to variations in both the bridging R group and the metal center. It was also observed that fluorescent decay of the first singlet state for the sample complexes were less than 0.5 ns.
