An imidazolium salt with a fused benzoferrocenyl was synthesized. This compound was used as an N-heterocyclic carbene (NHC) precursor, and the related ferrocenyl-imidazolylidene complexes Fc-NHC-MLn (MLn = IrCl(COD), IrCl(CO)2, AuCl) were synthesized and fully characterized, including the crystallographic characterization of some of the key structures. The oxidation of the iridium carbonyl compound Fc-NHC-IrCl(CO)2 with acetylferrocenium tetrafluoroborate afforded the oxidized ferrocenium-NHC-IrCl(CO)2 (Fe(III)) species; however the isolated product contained a byproduct resulting from the protonation of the starting Fe(II) complex. The analysis of the electron-donating character of the neutral ligand and the ligand resulting from the oxidation was carried out by studying the variation of the ν(CO) stretching frequencies of Fc-NHC-IrCl(CO)2 and its oxidized analogue, revealing that this shift is 2.9 cm–1, which is consistent with a decrease of the electron-donating character of the ligand produced by the ...