Tetrathiafulvalene (TTF) is an organosulfur compound with the formula H2C2S2C=CS2C2H2. It is the parent of many tetrathiafulvenes. Studies on these heterocyclic compound contributed to the development of molecular electronics, although no practical applications of TTF emerged. TTF is related to the hydrocarbon fulvalene (H4C4C=CC4H4) by replacement of four CH groups with sulfur atoms. Over 10,000 scientific publications discuss TTF and its derivatives.