A new oxidative C-O bond cleavage reaction-based probe FluHMPP was designed and prepared. FluHMPP displays excellent selective turn-on fluorescence response for Cu-II in aqueous solution under visible light excitation. The cleavage products are fully characterized. Fluorescein fragment is further oxidized to highly fluorescent MFME (3'-O-methylfluorescein methyl ester), and benzyl ether of imine fragment has been transformed to carboxyl. Confocal microscopy experiments have demonstrated that FluHMPP could also be used in live cells for the detection of Cu-II.