Halogen bonded cocrystal polymorphs of 1,4-di(4′-pyridyl)-1,3-diacetylene

Cocrystal polymorphs based on sym-triiodo-trifluorobenzene (IFB) with 1,4-di(4′-pyridyl)-1,3-diacetylene (DPDA) are formed with halogen bond interactions. Two cocrystal phases were obtained by using different solvents, acetonitrile and methylene chloride, and confirmed by their single crystal structure data. In the application direction, the different photo-physical properties of the two phases were discussed carefully.