Determination of the optoelectronic properties of the novel dithienopyrazines 5 and 6 revealed absorption maxima at 336 and 339 nm, respectively, and emissions at 379 nm in dichloromethane (DCM). Redox potentials, which were determined by cyclic voltammetry in DCM/tetrabutylammonium hexafluorophosphate (0.1 M), gave irreversible oxidation waves with peak potentials at Ep Ox = 1.52 V and 1.63 V vs ferrocene/ferricenium (Fc/ Fc + ) and reversible reduction waves with half wave potentails at E1/2 Red -2.19 V for both derivatives (Table ). HOMO and LUMO energies were determined using these potentials and setting the reference redox couple Fc/Fc + at -5.1 eV vs vacuum level. Thus, for the anti-derivative 5 a EHOMO level of -6.48 eV, a ELUMO level of -3.02 eV, leading to an energy gap Eg of 3.46 eV were determined. In the same way, the values for syn-derivative 6 were only marginally different and resulted in EHOMO = -6.56 eV, ELUMO = 3.04 eV, and Eg = 3.52 eV. Compared to the calculated HOMO and LUMO energy levels of heterotriacenes 5 and 6 (vide supra), our experimental data is in approximate agreement for the HOMO energies, but differ substantially for the LUMO energies, which are vastly overestimated by the calculations. Consequently, the energy gaps were also calculated oversized. . Experimental redox potentials, HOMO/LUMO energies, and electrochemical energy gaps of dithienopyrazines 5 and 6 in comparison to calculated data. Nevertheless, these results showed that the formal introduction of nitrogens into the benzodithiophene core led to a stabilization of both, HOMO and LUMO, by around 0.7-0.8 eV each in the dithienopyrazines transforming them to rather electron-deficient and less oxidation sensitive systems. These electronic properties become important for their reactivity in follow-up reactions, which is described in the chapter below.