A colorimetric and fluorescent chemodosimeter responding to Cu2+ with high selectivity and sensitivity

4-(dicyanomethylene)-2-methyl-6-[p-(dimethylamino)-styryl]-4H-pyran (DCMS) as a colorimetric fluorescent chemodosimeter for Cu 2+ was synthesized. DCMS can selectively recognize Cu 2+ without disturbance by other metal ions in acetonitrile. Furthermore, the DCMS solution showed a distinguishable color change visible to the naked eye after addition of Cu 2+ . DCMS for Cu 2+ sensing in acetonitrile had a remarkably low detection limit of 0.2 μM, which is 1 % of the toxicity level in drinking water defined by the US Environment Protection Agency (USEPA). Interestingly, the results suggest that the Cu 2+ sensing mechanism may be involved in a redox reaction between Cu 2+ and DCMS.