The reactions of diiminosuccinonitrile (DISN) with nucleophiles, acyl halides, and carbonyl compounds are described. Nucleophiles such as water, alcohols, and amines add to DEN giving products which result from displacement of either hydrogen cyanide or ammonia. Phosgene reacts with DISN to give a reactive imidazolidone from which several new polyfunctional derivatives have been prepared. Isoimidazoles, pyrazines, and oxazoles ...