Two quenching groups are better than one: A robust strategy for constructing HOCl fluorescent probe with minimized background fluorescence and ultra-high sensitivity and its application of HOCl imaging in living cells and tissues

•A robust strategy for probe design with dual-quenching groups in one probe.•The strategy has been applied for designing HOCl fluorescent probe successfully.•The strategy can both enhance the probe’s sensitivity and selectivity significantly.•The detection limit for HOCl is as low as 3.5 nM.•Two-photon probe has been used to detect HOCl in living cells and kidney tissues.