Experimental absorption spectra of 2T-N and 2T-7N from Refs. are shown as red lines in Figs. and, respectively. For both molecules, the lowest energy absorption band is very weak and is ascribed to a forbidden transition that gains intensity through vibronic coupling. This dark transition is located at ∼ 1-1.5 eV and ∼ 2.6-3 eV for 2T-N and 2T-7N, respectively. An intense and sharp transition is seen in 2T-N at ∼ 2.7 eV followed by a broad absorption for energies higher than ∼ 3.9 eV. The 2T-7N spectrum is similar but blueshifted, with the first intense absorption observed at 4-4.3 eV and a second broad absorption at energies higher than ∼ 5.3 eV. In the same figure, superimposed to experimental spectra, we show spectra calculated accounting for up to triple excitations (i.e., CISDT), as to ensure converged results (see below). Results are shown for different values of the on-site energy of the triangulene central nitrogen, ε py N . For both molecules, the lowest energy state, S 1 , is a dark state (A ′ 2 symmetry in the D 3h point group) and its location is marked by a cross in the figure.