Benzo[''c'']cinnoline is a tricyclic organic compound with the formula C12H8N2. Formally this species is derived by oxidative dehydrogenation of 2,2'-diaminobiphenyl. This heterocycle reacts with iron carbonyls to form C12H8N2Fe2(CO)6.[1]
R. P. Bennett, "Iron Carbonyl Complexes of Azo Compounds" Inorganic Chemistry, Volume 9, pp. 2184-6 (1970) (description of the first iron carbonyl derivative)