Synthesis of Azoaromatic Dyes via Redox Driven C−N Bond Fusion

Two novel organic azo-dyes (2+) that feature an intense intramolecular charge transfer transition with end absorption reaching into the NIR region are introduced. Syntheses of these compounds were achieved by an unusual redox-driven C−N bond fusion of the tricyclo azo-aromatic compounds (1+). The compounds show reversible electro- as well as proton chromism. The results have generated further scope of research in the area of designed syntheses of functional azoaromatics.