A simple and efficient dual optical signaling chemodosimeter for toxic Hg(II).

10-Methylthioacridone, designated as acrithion, has been employed as an easily accessible chemodosimeter for the optical targeting of toxic Hg(2+) in buffered aqueous DMSO. The Hg(2+)-mediated desulfurization of the probe is translated into selective dual signaling of Hg(2+) by means of color bleaching and fluorescence amplification while several other metal ions, including potentially competing Ag(+), Cu(2+) and Pb(2+), afford no significant interferences even in excess concentrations.