A chemosensor having a bipodal thiocarbamate scaffold attached to histidine moieties senses Hg2+ with a remarkable selectivity. The binding results in a 50 nm blue shift in the fluorescence spectra and a 19-fold enhancement of the fluorescence quantum yield of the ligand. In addition to the detection of Hg2+ visually under UV light in solution, the chemosensor was used for fabrication of paper strips that detected Hg2+ in aqueous samples. The sensor was also used for imaging Hg2+ in adult zebrafish and in human epithelial carcinoma HeLa S3 cells.