Endogenous peroxynitrite a highly reactive oxidant plays significant roles in various physiopathological processes in living organisms. Therefore, sensing and monitoring of peroxynitrite with accurate detection specifically, is an immense challenge. To address this issue, we synthesized a water soluble, mitochondria-targeting "turn-on" fluorescent probe (BICBzBF) for the detection of mitochondrial peroxynitrite. BICBzBF (pale yellow) demonstrated high sensitivity and selectivity in fluorometric tracing of peroxynitrite over other ROS/RNS tested. This arylboronate-masked probe responds to peroxynitrite, resulting in the corresponding phenol derivative; a strong fluorescence accompanied a change to red rose as observed by the naked eye. The probe responds to peroxynitrite within <120 s, shows a lower nanomolar detection limit (60.5 nM), exhibits a remarkable ca. 32fold intense increase. Taking these features fully into account, BICBzBF was evaluated in how it monitors peroxynitrite exogenously and endogenously. Moreover, BICBzBF successfully traced ONOO- in inflammatory living zebrafish animal model which are chemically induced for inflammation. The results obtained in both exogenous and endogenous studies demonstrate that BICBzBF actively detects ONOO-; major accumulation in retina and intestine indicate BICBzBF could serve as a potential molecular imaging tool in investigations of the role(s) played by peroxynitrite in a variety of physiological and pathological contexts.