A compound represented by the following general formula (I):wherein R1 represents an amino group which may be substituted with one or two alkyl groups R2, R3, R4 and R5 independently represent an alkyl group and R6 and R7 independently represent a monocarboxyalkyl group, a salt thereof, or an ester thereof, which is useful as a pH-sensitive fluorescent probe which emits intense fluorescence in an acidic region.
