where MET HOD i and REFERENCE i are the values of the property for the ith excimer, either D e or r e , and N the number of systems. An analysis of MADs is simply presented as a convenient metric to summarise the performance of a method across our four model structures, and we acknowledge a sample size of four does not offer MADs with statistical significance comparable to more comprehensive excited-state benchmarks. MADs for the nine functionals, with and without D3(BJ) and D4 dispersion corrections, compared to the SCS-CC2/CBS (3,4) reference are presented in Fig. , with corresponding numerical values reported in Table . † For the description of D e and r e , dispersion-uncorrected functionals display a descending trend for the MADs while ascending Jacob's Ladder (Fig. ). It should be noted that, for dispersion-uncorrected functionals, these deviations overwhelmingly correspond to underestimations of D e and overestimations of r e , whereas dispersion-corrected functionals vary in this regard (see ESI †). The largest errors in D e correspond to global hybrids and CAM-B3LYP yielding MADs in the order of 15.38 to 17.93 kcal/mol. Similarly, the largest MADs in r e range between 0.23 and 0.36 Å and are attributed to CAM-B3LYP, BHLYP and B3LYP, i.e. the global and RS hybrids with Becke88 exchange and LYP correlation. PBE38 gives a much smaller MAD of 0.10 Å, comparable to higher-rung DHDFAs.