Simple Strategy to Develop Multifunctional NIR Fluorescent Probes for Simultaneous Identification of H₂S and SO₂

H₂S and SO₂ have been considered as important gaseous signaling molecules in biological systems, functioning as regulatory roles in many physiological processes of organisms. To better understand the crosstalk and synergetic effects between H₂S and SO₂ in biological systems, developing a single fluorescent probe for dual-channel fast detection of H₂S and SO₂ is highly urgent. We herein report a simple strategy to develop multifunctional near-infrared (NIR) fluorescent probes for simultaneous identification of H₂S and SO₂. Based on the idea of modulating the reactivity of the benzopyrylium core with electron donors, two new NIR fluorescent probes (<b>SW1</b> and <b>SW2</b>) were synthesized and evaluated. The probe <b>SW2</b> could not only rapidly sense H₂S and SO₂ with different fluorescence signals but also be used as a reversible probe to investigate the flux of H₂O₂ and SO₂. Moreover, <b>SW2</b> was successfully applied in visualizing H₂S and SO₂ in living cells and mice. These results suggest that <b>SW2</b> could serve as a useful tool in understanding the complex relationships between H₂S and SO₂ in biological systems.