I. G. Farbenindustrie AG, commonly known as IG Farben, was a German chemical and pharmaceutical conglomerate. It was formed on December 2, 1925 from a merger of six chemical companies: Agfa, BASF, Bayer, Griesheim-Elektron, Hoechst, and Weiler-ter-Meer. It was seized by the Allies after World War II and split into its constituent companies; parts in East Germany were nationalized.
IG Farben was once the largest company in Europe and the largest chemical and pharmaceutical company in the world. IG Farben scientists made fundamental contributions to all areas of chemistry and the pharmaceutical industry. Otto Bayer discovered the polyaddition for the synthesis of polyurethane in 1937, and three company scientists became Nobel laureates: Carl Bosch and Friedrich Bergius in 1931 "for their contributions to the invention and development of chemical high pressure methods", and Gerhard Domagk in 1939 "for the discovery of the antibacterial effects of prontosil".