Structural Phase Transitions in Anthracene Crystals

Anthracene (C14H10) and its derivatives, π‐conjugated molecules in acenes, have been widely researched in terms of their reactions, physical properties, and self‐assembly (or crystal engineering). These molecules can be functionalized to tune reactivities, optoelectronic properties, and self‐assembling abilities. Structural changes in the molecular assemblies, solid states, and crystals have recently been discovered. Therefore, a systematic discussion of anthracene's molecular structure, packing, and optical properties based on its intermolecular structure and phase transitions is important for future chemical and structural design. In the present review, we discuss anthracene's molecular design, dimer packing, and crystal structure, focusing on the structural phase transitions of its crystals. We also provide examples of the phase transitions of anthracene crystals. Changes to edge‐to‐face of CH‐π interaction and face‐to‐face packing of π‐π interaction affect the thermodynamic stabilities of various crystal structures. These structures can inform the prediction of structural and physical properties. Anthracene and its derivatives have attracted great interest for their use in molecular research. This Review introduces the engineering of anthracene including synthetic design, reactivities, and optical properties toward structural phase transitions of the crystals.