Halogen-Bonded Cocrystals as Optical Materials: Next-Generation Control over Light–Matter Interactions

This review summarizes the recent advances in utilizing halogen bond-driven cocrystal formation as a design element in the creation of optical or photoresponsive materials, notably cocrystals and liquid crystals. The extensive work over a relatively short time has demonstrated halogen bonding as a versatile supramolecular interaction capable of creating libraries of fluorescent, phosphorescent, dichroic, photoswitchable, as well as photomechanical crystals and liquid crystals. Such rapid development, and the diversity of materials properties that have been designed or fine-tuned with success, signal the emergence of halogen-bonded cocrystallization as an exciting new playground for crystal engineers, chemists, and physicists to develop next-generation optical materials.