The different behavior observed for 2T-N and 2T-7N in terms of ∆E ST reflects the diverse nature of the triangulene rim in the two cases. In Fig. , we show the dependence of the ST gap on the parameters that define the triangulene rim, namely ε aza N and U aza N . The red dot on the map corresponds to the 2T-N parameters, where all rim atoms are C atoms. If, starting from this position, we decorate the odd sites on the rim with electron-withdrawing atoms, whose on-site energy becomes more and more negative, the ST inversion is lost when ε aza N becomes more negative than ∼ -2.1 eV. However, increasing the on site electron repulsion from the value relevant to C atoms to that relevant to N atoms, the ST inversion is favored. 2T-7N, with its six aza nitrogens on the rim, is precisely on the verge of the ST inverted region (green dot on the map). This last observation contrasts with the results of many allelectron calculations that typically predict a more pronounced ST inversion in 2T-7N than in 2T-N.. Of course, PPP model is not an exact model, and results are affected by the specific choice of the molecular geometry and model parameters (see ESI, Section S2 for specific illustrative cases). However, it is important to stress that all-electron calculations mentioned above all rely on up to double excitations. In these approaches, large uncertainties on π → π * transition energies are estimated (e.g., ∼ 0.11 eV for CCSD and ∼ 0.17 eV for ADC(2)), making the error on ∆E ST of the same order of magnitude as the calculated gap itself.