A novel coumarin-benzopyrylium based near-infrared fluorescent probe for Hg2+ and its practical applications

[Display omitted] •A novel coumarin-benzopyrylium based near-infrared fluorescent probe for Hg2+ has been synthesized.•The ring-open form of the probe exhibits NIR absorption (670 nm) and emission (720 nm) with a large emission shift (225 nm).•The probe allows for rapid detection (30 s) of Hg2+ with high sensitivity, high selectivity and low detection limit (6.94 nM).•The probe has used for sensing Hg2+ in food and biological samples. A novel colorimetric and ratiometric NIR fluorescent probe for Hg2+ was designed and synthesized based on a coumarin-benzopyrylium platform. The ring-open form of the probe exhibits NIR absorption (670 nm) and emission (720 nm). The probe shows high sensitivity, high selectivity and rapid response (30 s) to Hg2+. The detection limit was as low as 6.94 nM. The probe shows high stability in a wide pH range from 2 to 10. Moreover, the probe can be employed for detecting Hg2+ in food and biological samples.