Fluorescence-detected magnetic resonance and photoconductivity-detected magnetic resonance are simultaneously applied to the system of a radical-ion pair formed in the: photoinduced electron transfer reaction between pyrene and 1,3-dicyanobenzene. The former monitors the exciplex fluorescence via the singlet radical-ion pair, while the latter monitors free ionic radicals escaping from the radical-ion pair. Both spectra show good coincidence, which shows that the population of the singlet state is proportional to the total radical-ion pair one. The data obtained from the photoconductivity-detected magnetic resonance method suggest the faster quenching reaction of the triplet state of the radical-ion pair than that of the singlet state.