Abstract2,1,3‐Benzothiadiazolecarbonitriles,2, have been prepared by two different methods. Reaction of bromo‐2,1,3‐benzothiadiazoles,1, with cuprous cyanide occurs advantageously in refluxing dimethylformamide to give2, complexed with curpous bromide. Hydrogen peroxide in hydrochloric acid at 30–40° is shown to be an effective reagent for efficient decomposition of these reactions complexes,2CuBr, and subsequent isolation of2.Yields in the Sandmeyer method for preparing nitriles 2 were improved by diazotizing amino‐2,1,3‐benzothiadiazoles,3, with nitrosyl‐sulfuric acid prior to reaction with the cuprous‐sodium