IG Farben was a large German chemical conglomerate formed in 1925 through the merger of several companies. It became one of the world's largest producers of synthetic materials, including dyes, plastics, and pharmaceuticals. The company played a significant role in the development of synthetic rubber and fuel during the early 20th century. During World War II, IG Farben was involved in the production of chemicals for the Nazi regime, including the infamous Zyklon B, used in concentration camps. After the war, the company was dismantled due to its association with the Nazi regime and its unethical practices, leading to the creation of several smaller companies.