Importance of Organic Synthesis in the Development of Liquid Crystals

Liquid crystals are fascinating materials in many areas of applied science. They are widely known for their application in display technology and uses in other fields have also recently been identified, such as anisotropic networks, organic light-emitting diodes and photo- and semiconducting materials. Further applications in new areas continue to be developed, as well as effective solutions to problems associated with the limitations of liquid crystals. Designing novel thermotropic liquid crystals for applications in advanced functional materials involves the selection of a suitable central core, linking group and terminal functionality. Over the years, a very large number of heterocyclic compounds containing liquid crystal units have been synthesized. Interest in this field of research has increased considerably in recent years due to improvements in synthetic methodologies. This critical mini-review describes some basic design principles and synthetic approaches to prepare the most commonly found liquid crystals, especially fivemembered nitrogen heterocycles, such as 1,2,4- and 1,3,4-oxadiazols, isoxazole, 1,2,3-triazole, 1,3,4-thiadiazole, 1,3-thiazole and 2,1,3- benzothiadiazole.