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 (SW1 and SW2) were synthesized and evaluated. The probe SW2 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, SW2 was successfully applied in visualizing H₂S and SO₂ in living cells and mice. These results suggest that SW2 could serve as a useful tool in understanding the complex relationships between H₂S and SO₂ in biological systems.