While the recently reported use of quinonefunctionalised electrodes is promising, questions remain about the molecular mechanism of this process and whether it is possible to increase its oxidative stability by carefully tuning the electron density of the quinones. In the presence of oxygen (O 2 ), it is observed that there is a loss in CO 2 capture ability as reduced quinones can be re-oxidised while O 2 is reduced. If quinone structures are tuned to have sufficiently positive reduction potentials by substitution of functional groups on the aromatic rings, it may be possible to avoid the side-reactions with O 2 . However, by tuning the redox potentials, one will also change the CO 2 capturing ability of the quinones. Early experimental work by DuBois first illustrated the trade-off between reduction potentials and CO 2 binding constants. They found a linear relationship between the CO 2 binding constant and the second reduction potential for a series of 4 functionalised benzoquinones and phenanthrenequinone. More recent experiments on benzoquinones have supported this trade-off, while other studies have further explored how functionalisation impacts the chemistry of electrochemical CO 2 capture by quinones. Despite this progress, a complete assessment of the relationship between redox potentials and CO 2 capturing abilities in a wide range of redox-active molecules has not been carried out. We believe this is because (i) quantifying the thermodynamic driving force of CO 2 capture through CV experiments alone is challenging and (ii) a systematic electrochemical study of quinone derivatives with different numbers of substituents and different functional groups is not easily accessible experimentally. Both of these challenges can be tackled computationally through quantum chemical calculations. As quinones and their derivatives are also of interest in energy storage applications, several studies have computationally examined their redox properties, including the effect of electron-donating groups (EDGs) and electron-withdrawing groups (EWGs), substituent pattern effects and their structure-property relationships. Most of these works are based on density functional theory (DFT), which has proven to be an affordable and reliable way to study redox properties of organic molecules. It is worth emphasising that these previous studies, however, did not examine electrochemical CO 2 capture.