Two imidazol(in)ium-dithiocarboxylates have been investigated as sensors for the detection of mercury ions and silver ions. They could be applied as colorimetric chemosensors for the detection of Hg2+ and Ag+. Furthermore, an additional sensory input was found by a colorimetric change of a two-phase system from the organic phase into the aqueous phase. Due to different colors at different ratios of the betaines and Hg2+ it is possible to estimate the concentration of Hg2+ with the ”naked eye”.