The first photophysical study of addition derivatives of C-70 is reported. The spectroscopic and photophysical properties of the singlet and triplet states of these compounds have been determined using a combination of time-resolved and steady-state techniques, including picosecond single photon timing, laser; flash photolysis, and low-temperature polarized fluorescence Electronic absorption, fluorescence, and phosphorescence spectra are red-shifted with respect to those of C-70 AS With the parent fullerene, the main deactivation channel of the excited singlet state is intersystem crossing, and the yield of singlet oxygen formation is close to unity. Most of the measured photophysical parameters such as the fluorescence lifetime, and fluorescence quantum yield, are similar, but not identical, to those of C-70 Fluorescence polarization shows that the emission transition moment is located in the xy plane, like in C-70 and that the effective fluorophore symmetry remains high.