triangulenes is computationally very demanding even for PPP (as shown in Table ), making their use in exploratory studies prohibitive. The PPP-RASCI approach, combined with the hole/particle approximation, represents an excellent compromise between computational efficiency and accuracy. By defining a reduced active space RAS2 containing 4 electrons and 6 molecular orbitals, one can achieve convergence to CISDT results by considering a reduced number of single excitations involving RAS1 and RAS3 subspaces.