InteresTngly, Yan et al. proposed a very similar complex, o-ICz-Ir (Figure ) with the pyridine moiety aUached para to the iCz nitrogen center rather than ortho as in the previous example. The authors proposed that in this posiTon, methyl and tert-butyl groups impose a steric interlocking that minimizes ligand vibraTons, affording a narrower and blue-shiged emission (λPL = 527 nm; FWHM = 27 nm in toluene) compared to Ir(py-iCz)2(tdm) (λPL = 567 nm; FWHM = 42nm in toluene). Yan et al. reported a bright red emiUer, ICzqz-Ir (λPL = 605 nm and FPL = 86% in hexane), achieved by making the coordinaTng moiety of the C^N ligand much more p-accepTng (Figure ); 10 notably, this complex is much brighter than the parent emiUer, piq-Ir (FPL = 68% in hexane). Liao et al. invesTgated the effect of nitrogen-doping in the iCz moiety in Ir(NICz)2(tdm). This structural change leads to a blue-shiged emission (λPL = 500 nm in DCM). compared to Ir(py-iCz)2(tdm) (λPL = 567 nm in DCM) and o-ICz-Ir (λPL = 527 nm in toluene). Thus far, there has been no invesTgaTon into the replacement of the coordinaTng heterocycle of the C^N ligand with a more s-donaTng imidazolyl-based NHC unit nor has there been any exploraTon of iCz-containing complexes in families other than those that contain a non-chromophoric tdm ligand. The use of an NHC moity typically leads to a blue-shiged emission. In this report we have designed an NHC-iCz ligand and employed it as an ancillary ligand in Ir(dFppy)2(iCzmi) (Figure ) (where dFppy and iCzmi are 3,5-difluoro-2-(2-pyridinyl)phenyl and N-indolo[3,2,1-jk-carbazole]-N'methylimidazolium, respecTvely) and compared its photophysical properTes to its parent complex Ir(dFppy)2(pmi), previously reported by Li et al.