The electrochemical performance of the synthesized OTQC was additionally evaluated in a Zn-organic cell using an aqueous 3 M ZnSO4 electrolyte. OTQC exhibited similar charge/discharge curves as in the lithium system, with an initial plateau at around 1.2 V, which gradually transformed into a sloping curve (Figure ). In comparison with TQC, OTQC exhibited a slightly higher maximum capacity (326 mAhg -1 vs. 301 mAhg -1 ) and a higher average discharge voltage (0.86 V vs. 0.76 V). In contrast to the good cycling stability in the lithium system, OTQC showed significant capacity fading in the Zn battery delivering capacity retention of 42 % after 400 cycles at 100 mAg -1 (Figure ). The rate performance test in the Zn system showed better reversibility without any overcharging at higher rates as seen in the lithium system (Figure ). At the highest rate of 10 Ag -1 , the system reached a capacity of 47 mAhg -1 (21 % of the capacity obtained at 100 mAg -1 ) (Figure ). In our recent report, we have shown that the use of less polar 2.2 M Zn(OTf)2 in 70 % PEG electrolyte improved the cycling stability of a small organic cathode material TQD in a Zn-organic battery. The use of the aforementioned electrolyte decreased the specific capacity of OTQC, which reached a maximum value of 224 mAhg -1 , but on the other hand, drastically increased the cycling stability, reaching 91 % capacity retention after 45 cycles at 100 mAg -1 (Figure We employed several spectroscopic and electrochemical methods to determine the redox mechanism of OTQC in the OTQC-Zn battery (Figure ). Ex-situ FT-IR measurements of the electrodes in different states of charge revealed that upon discharging to 0.9 V the peak at 1714 cm -1 associated with the carbonyl (C=O) stretching vibrations almost completely disappeared, which together with the absence of peaks above 3300 cm -1 associated with -NH and -OH vibrations suggests coordination with Zn 2+ ions (Figure , green). Discharge from 0.9 V to 0.25 V showed the emergence of peaks at 3400 -3600 cm -1 attributed to the -NH or -OH stretching vibrations, indicating H + insertion (Figure ,b, blue). The peaks associated with H + insertion were only observed in the OTQC-Zn battery and were absent in the water-free OTQC-Li battery (Figure ). Recharging to 1.6 V exhibited reemergence of the peaks observed in the pristine electrode, signifying the reversibility of the redox process. Co-insertion redox mechanism of Zn 2+ and H + has already been reported for several other organic cathode materials. Content not peer-reviewed by ChemRxiv. License: CC BY 4.0 (black, 5 th cycle), 2.2 M Zn(OTf)2 in 70 % PEG (red, 2 nd cycle), and 3 M ZnSO4 (blue, 2 nd cycle). f) Ex-situ UV-VIS spectrum of electrodes submerged in 3 M ZnSO4 at different states of charge: discharged to 0.9 V (green), discharged to 0.25 V (blue), and charged to 1.6 V (brown).