This paper studies the intramolecular photoinduced electron-transfer （PET） of covalent bonded azobenzene-perylene diimide （AZO-PDI） in solvents by using steady-state and time-resolved fluorescence spectroscopy together with ultrafast transient absorption spectroscopic techniques. Fast fluorescence quenching is observed when AZO-PDI is excited at characteristic wavelengths of AZO and perylene moieties. Reductive electron-transfer with transfer rate faster than 10^11 s^-1 is found. This PET process is also consolidated by femtosecond transient absorption spectra.
