meV when transformed from a distorted to a planar configuration. With regards to electron correlation, an increase in the number of unpaired electrons and degenerate frontier orbitals will generate a greater Coulomb repulsion between the spins located on the same monomer, as the TRI dimer with four unpaired electrons has a larger ΔEspin than other diradicaloids with two unpaired electrons (Table ). As a result, the search for non-Kekule building blocks, such as Clar's goblet and other triangulene systems with unpaired π-electrons, holds great promise for the discovery of metal-free magnetism with strong electron correlation.