Dual colorimetric and near-infrared fluorescence probe for Hg2+ detection and cell imaging

•A near-infrared fluorescent probe based on malononitrile isophorone.•For detection of Hg2+ in the environment and live-cell fluorescence imaging.•Using thioacetal as the detection group, the sulfur in this group can specifically combine with Hg2+.•The fluorescent probe has good selectivity and good detection speed.