Natural and anthropogenic activities leading to excessive toxic biological anions in water have warranted the development of anion sensors, especially for cyanide (CN⁻) and fluoride (F⁻) ions in aqueous media. Herein, a contemporary synthetic route to embed organochalcogen compounds (–SPh and –SePh) in a boron-functionalized imidazole scaffold via metal halogen exchange is reported. Upon methylation, fluorogenic compounds 5-dimesitylboryl-2-phenylthio-1-methylimidazole (7) and 5-dimesitylboryl-2-phenylselone-1-methylimidazole (8) form the corresponding imidazolium salts, 5-dimesitylboryl-2-phenylthio-1-methylimidazolium iodide (9) and 5-dimesitylboryl-2-phenylselone-1-methylimidazolium iodide (10), which are non-luminescent. All of the compounds are thoroughly characterized, and their utility in sensing F⁻, CN⁻, and various other biologically relevant halides has been studied through UV-vis and fluorescence spectroscopy. The substrates and products of 1 : 1 binding of anions (F⁻/CN⁻) with the compounds have been established by spectroscopy, spectrometry, single-crystal X-ray crystallography, and first principles quantum mechanical theoretical calculations. The superior binding ability and micromolar sensitivity towards CN⁻ ions over other anions in aqueous media were elucidated. The reversibility of compound 7 was also tested and it was found that fluoride binding was reversible while cyanide binding was not.