We describe a catalytic strategy for direct single C(sp3)-F bond alkylation of trifluoromethylbenzimidazoles under a photoinduced thiol catalysis process. The CO2 radical anion (CO2•-) proved to be the most efficient single-electron reductant to realize such a transformation. The spin-center shift of the generated radical anion intermediate is the key step in realizing C-F bond activation under mild conditions with high efficiency.