A simple fluorescent probe for glutathione detection and its bioimaging application in living cells

•Two simple fluorescent probe HPY1, 2 for detecting GSH over Hcy and Cys were proposed.•The sensing mechanism of HPY1, 2 to GSH were studied by fluorescence change experiments, HRMS and DFT calculation.•HPY1, 2 have low detection limits, excellent sensitivity and high selectivity for GSH.•HPY1 was successfully applied to imaging of both endogenous and exogenous GSH in L929 cells.