Benzothiophene is an aromatic organic compound with the molecular formula C8H6S and a naphthalene-like odor. Benzothiophenes are used in research as a starting material for the synthesis of larger, often biologically active structures. It exists in medicinal chemical structures such as raloxifene, zileuton, and sertaconazole, and can also be found in BTCP. It is also used to make dyes such as thioindigo.
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.