Intending to improve the TQC material we introduced the additional redox active motifs into the structure. That was done by the replacement of the redox inactive benzene units with the redox active quinone units (Figure ). A similar transformation has already been applied in organic cathode materials, where the oxidation of the benzene unit was achieved by refluxing the precursor with potassium dichromate (K2Cr2O7) in a diluted sulfuric acid. Employing the same precursor for the oxidation of TQC led to only a trace amount of insoluble product, presumably because of too harsh conditions. Using less harsh conditions by replacing the solvent with glacial acetic acid solved the problem and we obtained OTQC (Figure ). Similar to the TQC, OTQC's low solubility in the commonly used NMR solvents prevented the characterization with liquid NMR. Successful oxidation of the material was therefore confirmed with the use of multiple other techniques. A comparison of C MAS NMR spectra between TQC and OTQC shows the emergence of another peak at 177.9 ppm attributed to the carbonyl unit (C=O) in the newly formed quinone structures (Figure , red). Furthermore, the introduction of additional carbonyl units was confirmed by FT-IR with the appearance of a strong peak at 1714 cm -1 attributed to the (C=O) stretching vibrations (Figure ). Successful oxidation of TQC was additionally confirmed with MALDI-TOF MS spectra, which revealed Content not peer-reviewed by ChemRxiv. License: CC BY 4.0 the disappearance of peaks associated with the TQC (Figure , black) and the emergence of peaks at higher m/z attributed to the oxidized products (Figure , red). Although we expected the formation of pure dimer OTQC (Figure ), MALDI-TOF MS spectra revealed two major sets of peaks, one at around 586 Da attributed to the formation of dimer OTQC and another at around 793 Da attributed to the formation of trimer OTQC with hexaazatriphenylene core (Figure ). A possible explanation for the formation of trimer OTQC was derived from the low yield of the synthesis (42 %), suggesting a partial hydrolysis of the TQC during the oxidation. According to the literature , we presume that there is a dynamic reversible reaction in the inner pyrazine units of the TQC or its oxidation products, which can be hydrolyzed to aromatic diamines and reformed. Formation of the hexaazatriphenylene core is achieved through the reaction of the aromatic diamine and the free o-benzoquinone unit in the TQC. We need to emphasize that both products are electrochemically active, however, the trimer has a lower specific capacity. HOMO/LUMO energy levels for compounds studied in this work (Figure ) were calculated with the use of the density functional theory (DFT). The comparison between TQC and OTQC revealed that the TQC exhibits a lower energy gap (Eg) between HOMO and LUMO orbitals, which suggests that oxidized products possess lower intrinsic electronic conductivity. The calculations showed a big variability between energy levels of the LUMO orbitals connected to the electronic affinity of the molecules ranging from the lowest value of -4.23 eV in the dimer OTQC to the highest -3.44 eV in catechol TQC. Lower LUMO energy, lower energy gap, and higher amount of redox-active centers within the dimer OTQC in comparison with the trimer OTQC suggest the improved electrochemical properties of the dimer OTQC. The galvanostatic experiments were performed in a Swagelok cell using organic cathode and metallic lithium separated by the separator soaked with 1 M lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) in 1:1 (v/v) 1,3-dioxolane (DOL) and 1,2dimethoxyethane (DME) as an electrolyte in the voltage range of 1.5 -3.8 V and 1.65 -3.8 V for TQC and OTQC, respectively. Using a wider voltage window of 1.5 -3.8 V for OTQC resulted in higher specific capacity but lower cycling stability (Figure ). The comparison of galvanostatic charge/discharge curves between TQC and OTQC showed considerable differences (Figure ). Charge/discharge curves of the TQC exhibited a single-sloping curve.