An AIE based tetraphenylethylene derivative (MOTIPS-TPE) with a pyridinium pendant was synthesized for light-up sensing of F⁻ in aqueous solution without additives. The fluoride ion promoted cleavage reaction gave MOTIPS-TPE high selectivity toward F⁻ over other common anions. Moreover, MOTIPS-TPE can be used to monitor F⁻ in living HeLa cells.