The synthesis, characterization, and reactivity study of a square planar iron(II) biphenyl-2,2′-diyl complex [(IPr2Me2)2Fe(But2Bip)] (1, IPr2Me2=1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene, But2Bip=4,4′-di(tert-butyl)biphenyl-2,2′-diyl) has been performed. Complex 1 was prepared by the salt elimination reaction of (IPr2Me2)2FeCl2 with 2,2′-dilithium-4,4′-di(tert-butyl)biphenyl. Characterization data obtained from NMR spectroscopy, X-ray crystal structure determination, solution magnetic susceptibility measurement, 57Fe Mössbauer spectroscopy, in combination with DFT calculations, suggest the intermediate-spin ferrous nature of the iron biphenyl-2,2′-diyl complex. Complex 1 reacts with PhCCPh, EtCCEt and PhCN to form 2,7-di(tert-butyl)-9,10-diphenylphenanthrene (2), 2,7-di-tert-butyl-9,10-diethylphenanthrene (3), and 3,8-di(tert-butyl)-6-phenylphenanthridine (4), respectively, whereas, its interaction with AdNC and CO lead to the formation of the six-coordinate iron(II) biphenyl-2,2′-diyl complexes [(IPr2Me2)2Fe(But2Bip)L2] (L=AdNC, 5; CO, 6). The attainment of 2–4 supports the proposed mechanisms that involve ferroles as key intermediates in iron-catalyzed cycloaddition reactions.