Hexaazatriphenylene (HAT) derivatives: from synthesis to molecular design, self-organization and device applications

Dipyrazino[2,3-f:2′,3′-h]quinoxaline also known as 1,4,5,8,9,12-hexaazatriphenylene (HAT) is an electron deficient, rigid, planar, aromatic discotic system with an excellent π–π stacking ability. Because it is one of the smallest two-dimensional N-containing polyheterocyclic aromatic systems, it has been used as the basic scaffold for larger 2D N-substituted polyheterocyclic aromatics. Furthermore, it is the building block of choice in a plethora of molecular, macromolecular and supramolecular systems for a variety of applications. This review is aimed to critically review the research performed during the almost three decades of research based on HAT from the synthetic, theoretical and application points of view. The design principles and synthetic strategies towards HAT derivatives will be established and their use in n-type semiconductors, sensors, nonlinear optical chromophores, liquid crystals, microporous polymers for energy storage and nano and microstructures will reveal the relevance of HAT as a basic scaffold in the areas of organic materials and nanoscience.