The process to calculate a vibrationally coupled emission spectrum also identifies the main vibrational modes that contribute to the spectral shape. Visualisation of these vibrational modes can be used to identify the parts of the molecule where damping these vibrational modes could have a significant positive impact on the spectral profile. We first modelled the vibrationally coupled emission spectra of three widely studied green-emissive iridium complexes, fac-Ir(ppy)3, Ir(ppy)2(acac) and Ir(ppy)2(pic) (ppy = 2-phenylpyridinato; acac = acetylacetonate; pic = 2-piconilate) using the Adiabatic Hessian (AH) method, which has been demonstrated to work well for phosphorescent iridium complexes. Figure shows a comparison of the experimental and simulated emission spectra for fac-Ir(ppy)3, IrPic and Ir(ppy)2(acac). The major vibrational modes that contribute to the secondary vibrational peak in the emission spectra at around 580 nm are tabulated in Table . The vibration of fac-Ir(ppy)3 can best be described as a ring breathing mode of the pyridyl ring from one of the ppy ligands, with significant contribution from the attached phenyl ring, as well as some minor involvement of the other ligands. The vibration of Ir(ppy)2(acac)