Solid-state emission spectra were collected for compounds 1-Eu•0.5MeCN and 1-Yb•0.5MeCN to probe the symmetry and electronic structure. Both compounds were measured at room temperature, while an additional measurement at 77K was taken for 1-Yb•0.5MeCN to minimise the population of higher CF states and reduce thermal broadening of peak. In all cases, an excitation wavelength of 280 nm was employed, involving excitation via the tpa ligand. Compound 1-Eu•0.5MeCN exhibited peaks consistent with C3-symmetry (Figure ), with 5 D0 → 7 FJ (J = 1, 2, 3, 4, and 6) bands apparent at 593, 614, 650, 679 and 815 nm. The hypersensitive 5 D0 → 7 F2 transition is the most intense and responsible for the observed red emission. The magnetic dipole allowed 5 D0 → 7 F1 manifests as a single peak. In trigonal geometries the 7 F1 state splits into doublet (MJ = ±1) and singlet (MJ = 0) states in the presence of a strong CF. The observation of a single peak is indicative of a weak CF perturbation on the Eu 3+ centre. A weak 5 D0 → 7 F3 transition is indicative of minimal J-mixing, consistent with the high symmetry present. The relatively weak 5 D0 → 7 F4 is consistent with other C3symmetric Eu 3+ complexes, and the very weak 5 D0 → 7 F6 is expected for a Eu 3+ emission. to |±7/2⟩ states. However, a significant difference in the total CF splitting is apparent (825 and 526 cm -1 , respectively), which is in agreement with previous studies. These differences are consistent with the slightly higher measured χMT across the entire temperature range (compared to calculated), owing to smaller predicted CF splitting and therefore greater population of the more magnetic excited states. Elucidation of SMM properties is contingent on understanding the electronic structure of the ground J-multiplet, a venture which, to date, is highly dependent on computational predictions. The repeated observation of discrepancy between Yb 3+ CASSCF and experimental CF splitting is a potential linchpin for misguided studies in the targeting of Yb-based SMMs.