Fischer worked on his doctoral thesis as an assistant to Professor Walter Hieber in the Inorganic Chemistry Institute, His thesis was entitled "The Mechanisms of Carbon Monoxide Reactions of Nickel(II) Salts in the Presence of Dithionites and Sulfoxylates". After receiving his doctorate in 1952, he continued his research on the organometallic chemistry of the transition metal and indicated with his lecturer thesis on "The Metal Complexes of Cyclopentadienes and Indenes" that the structure postulated by Pauson and Keally might be wrong. Shortly after he published the structural data of ferrocene, the sandwich structure of the η5 (pentahapto) compound. He was appointed a lecturer at the TU in 1955 and, in 1957, professor and then, in 1959, C4 professor. In 1964 he took the Chair of Inorganic Chemistry at the TU.