Having established the accuracy of our experimental methods via the well-studied ICT excited-state of DMABN, we turn to the more complex topic of the cationic photoredox catalysts [Ir[dF(CF 3 )ppy] 2 (dtbpy)]X (abbreviated: Ir[tBu]-X). Here, we expect a metal-to-ligand charge transfer (MLCT) state that is analogous to the ICT state of DMABN, but the presence of multiple ligands, large-spin-orbit coupling due to Ir(III) (ξ c,Ir = 3909cm -1 vs. ξ c,soc,Ru(II) = 990cm -1 ) , and ion pairing in a low dielectric constant solvent introduce new and unexpected dynamics. Below, we show that the highly mixed excited-states of our energetically similar ligands manifests as charge transfer processes from dF(CF 3 )ppy to dtbpy on the ns timescale. Meanwhile, contact-ion pairing introduces an intermolecular dipole moment between the two ionic species that dramatically changes the dipole of the excited-state through additional nuclear reorganization. These latter two effects vanish for a more weakly bound anion, whilst a flip-flopping inter-ligand charge transfer behavior at early times is consistent in both. We control ion pairing in Ir[tBu]-X in 1,4-dioxane by tuning the size of the anion (X -). Using PF - 6 as the counter ion is expected to result in contact-ion pairing in 1,4-dioxane due to its small size in relation to [Ir[dF(CF 3 )ppy] 2 (dtbpy)] + (abbreviated: Ir[tBu] + ), whereas using the much bulkier tetrakis[3,5-bis(trifluoromethyl)phenyl]borate 1-(BAr F- 4 ) should shift the dissociation equilibrium so that contact-ion pairs no longer form, as Ir[tBu] + and BAr F- 4 are relatively the same size. As with DMABN, measuring the characteristics of the microwave cavity as a function of the Ir[tBu]-X concentrations allows us to obtain their ground-state dipole moments. However, an additional complexity in this context is that it is necessary to make an assumption about whether contact-ion pairing takes place in order to calculate the rotational relaxation time of the complex, which can change significantly when the ion pair rotates as a unit. The approach we take here is to test each possibility (contact-paired vs. not) and observe whether the dipole moment we calculate is consistent with basic chemical theory and literature calculations. This provides an excellent method for assessing ion pairing in the ground-state of these complexes. The results of these elementary calculations are displayed in table 2.