C22-X and PC113-X series (Figure ) reveal that the dimer E 5% never exceeds the emission energy of any of its monomers. In each dimer, although the ΔE 7829: slightly increases the energy of the first LE state for both X and C22 (cyan and grey lines), the lowest monomer LE state energy is still close to the monomer emission energy (blue and black-dashed lines in