Possibly, the most surprising result from Fig. is the observation that just the 2T-7N rim, without the central N atom, has the largest negative ST gap, suggesting that the triangulene structure itself is not really needed to observe the ST inversion. On the other hand, coming back to our prototypical dyes, 2T-N and 2T-7N in Fig. , it is clear that the ST inversion is favored when the on-site energy on the central N is more negative, i.e. in systems where the two electrons from the central N are marginally involved in the rim physics. Fig. shows the HF frontier orbitals calculated for the cyclododecahexaene and hexaazacyclododecahexaene molecules, corresponding to the rims of the 2T-N and 2T-7N molecules. In the cyclododecahexaene the lack of spatial separation between HOMO and LUMO is reflected in a large exchange energy: the molecules (a simple cyclic polyene) does not qualify as an MR-CT dye. On the other hand, the frontier orbitals of the hexaazacyclododecahexaene variant, with their small K H-L value, confirm its MR-CT nature. Dynamical spin polarization was early discussed in the framework of π-electron models demonstrating very clearly that electron correlations govern ST inversion, but that at least double excitations are needed to capture the phenomenon. To shed light on the elusive dynamical spin polarization issue, we performed calculations on (CN) x rings, putting the 2x atoms in the vertices of regular polygons with bond lengths equal to 1.4 Å. Fig. shows (see ESI, Fig. ). The adopted idealized geometry is not realistic for all structures, but for the triazine molecule (i.e., x = 3) whose equilibrium geometry corresponds to a (almost) regular hexagon. For this specific molecule, it is therefore interesting to compare the PPP ST gap value, ∼ 0.65 eV, with available results from all-electron calculations, pointing to a positive ST gap, ∼ 0.9 eV. The agreement is far from perfect, but definitely acceptable for a semiempirical approach.