An on-off-on fluorescent bis(salamo)-like probe was developed for continuous and fast identification of Cu2+ and S2-

• A new bis(salamo)-like fluorescence sensor TBS was explored. • The probe can continuously recognize Cu 2+ and S 2− ions, and has strong anti-interference ability. • The mechanism of probe TBS was determined. • The probe can be used as a simple test strip for continuous detection of Cu 2+ and S 2− ions. A new bis(salamo)-like fluorescent probe TBS was constructed to realize continuous and fast identification of Cu 2+ and S 2− . Under an ultraviolet lamp, the probe TBS solution′s color changed from yellow to brown when copper(II) salt was added. However, when sodium sulfide was added, the solution′s color returned to yellow with a small amount of black solid precipitation at the bottom, indicating that the probe TBS has a fluorescence quenching effect on Cu 2+ . The addition of S 2− ion, fluorescence recovery was also observed. Experiments on ion selectivity, anti-interference and fluorescence titration of probe TBS on Cu 2+ and S 2− were carried out by fluorescence spectrometer. It was proved that probe TBS has the characteristics of high selectivity, strong anti-interference ability and fast response speed. The mechanism of continuous recognition of Cu 2+ and S 2− ions by probe TBS was proposed by job working curve, mass spectrometry and DFT studies. More importantly, the probe TBS can be made into a simple test strip for detecting Cu 2+ and S 2− ions in the environment, which greatly enhances the practical application value of the probe.