Reaction-based fluorescent sensor (L) based upon a conjugated benzothiazol structure was synthesized and used for detection of bisulfite (HSO3-) in water. L displayed large change in both fluorescence and absorption spectra immediately after the addition of HSO3-. It can be easily observed about the fading of the solution's color through the naked eye. The HSO3- underwent a 1,4-addition reaction with the C-4 atom in the ethylene group. The detection limit of L for HSO3- was measured to be 0.45 mu mol/L. The live cell fluorescent experiments proved the potential application of the L in tracing the HSO3- in future biological systems. (C) 2018 Elsevier B.V. All rights reserved.