In a previous study, we found a strong linear correlation between the HOMO-LUMO gap of the oligomer's singlet state and the stability of its triplet . That is, oligomers with a low HOMO-LUMO gap lead to a stable open-shell electronic structure due to the frontier molecular orbitals being closer energetically. Oligomers with a triplet ground-state tend to have a biradical electronic structure, in which each electron is found in a separate singly-occupied molecular orbital (SOMO).