Theoretical study of 3,3′ substitution of 9,9,9′,9′-tetramethyl-fluorene-dimers

► We study the substitution with electron donor and attracting groups in fluorene dimers. ► Optical properties can be tuned by the substitution of the fluorene backbone. ► Electronic excitations are assigned mainly to π → π∗ transitions. ► Linear correlations were found among EHOMO, EHOMO-LUMO and μ versus σp.