Diketopyrrolopyrroles: Synthesis, Reactivity,and Optical Properties

First reported by Farnum as much as 40 years ago, diketopyrrolopyrroles (2,5-dihydropyrrolo[4,3- c ]pyrrolo-1,4-diones) are currently one of the most widely used dyes, with applications that span high-quality pigments, fi eldeffect transistors, bulk-heterojunction solar cells, dye-sensitized solar cells,and fl uorescence imaging. Due to the breadth of their utility, there have been several foc…