Triazines are an important class of six-membered aromatic heterocycles with three nitrogen atoms that give rise to three regioisomers: 1,2,4-triazines, 1,2,3-triazines, and 1,3, 5-triazine. 1,2,3-Triazines show remarkable reactivity and have attracted attention for their medicinal value. Triazine compounds fused with other carbon and heterocycles are stable and have a broad spectrum of pharmacological activities.
The two N atoms in Benzothiadiazole could possibly form intermolecular hydrogen bonding, leading to a more planar backbone. Benzothiadiazole is a strong electron-accepting molecular fragment. By fusing it with thiazole donor-acceptor dyes, near-infrared fluorescence was created. The benzothiadiazole ring is a useful n-type building block for designing electron-transport materials for organic and polymer light-emitting diodes (LEDs). Arene- and heteroarene-fused thiadiazoles have also found use in the design of low-band-gap materials for the construction of organic field-effect transmitters (OFETs), as stable organic radicals, and as one or two photon-absorbing materials for the design of nonlinear near-infrared (NIR) dyes. Benzothiadiazoles acting as the electron-accepting cores have been incorporated into dendrimer-type light-harvesting materials.