A synthetic fluorescent sensor (sensor 1) is developed using boron-dipyrromethene as a fluorophore and phenoxo-bridged dipicolylamine as a receptor. Sensor 1 shows a significant enhancement of fluorescent intensity and a high selectivity for Zn2+ over various metal cations. The electrochemical study provides a rationale for the fluorescence turn-on of sensor 1 upon complexation with Zn2+ by the blocking of the photo-induced electron transfer mechanism. Sensor 1 can be used to image Zn2+ in A549 cells.