Abstract: As spectral sensitizers, the indolyl-10H-pyrido[1,2-a]indolium perchlorates I_a～k were synthesized. The UV and FL spectra of I_a～k bave been studied. In UV spectra, good correlation between λ_max¹ and substituent constants Δσ⁺ (σ_p⁺-σ_m⁺) was obtained. In FL spectra, the intramolecular energy transfer was observed. The spectral sensitization for polyvinylcarbazole (PVCz) of I_a～k has been tested. It was found that the sensitivity of PVCz/TNF was increased witb addition of I (R=NMe₂).

Key words: pyridoindolium salt, substituent effect, intramolecular energy transfer, spectral sensitizer