Pentaerythritol (PE) is considered a biodegradable material that combines the ease of synthesis, nonvolatility, and extra stability under basic conditions (acidic gas,sequestration, e.g, CO2), which makes it a useful candidate 'for postcombustion capture 1(PCC) application. To overcome corrosion problems,associated with CO, binding organic liquids, a "binarye mixture comprised of PE/1,8-diazabicyclo-[5,4,0]-undec-7-ene (DBU) (1:4 molar ratio) dissolved in dimethyl sulfoxide (DMSO) was exploited for CO, "capturing The forination 'of ionic alkyl organic carbonate (RCO3- DBUH+) was confirmed using 13c NMR (157.4 ppm) and ex situ attenuated total reflectance Fourier: transform infrared spectroscopy (ATR-FTIR) (two peaks were identified, viz., 1670 arid 1630 Cm-1, which were ascribed to the symmetric and asymmetric stretching of both CO and O-C-O- within RCO3H and RCO3-, respectively). The charged adduct was measured using a thermostated beaker coupled with conductivity and pH meter probes. The sorption capacity of a 5.0% PE (w/v) solution was measured. volumetrically with high efficiencies as, ca. 16 and 18.5 wt for wet and dry conditions,"respectively. In addition, density functional theory (DFT) was. performed to understand.the 'mechanism of action in the case of H2O, and simple alcohols, e.g., methanol and ethanol, Moreover, we reported on the newly discovered medium-dependent proton shuttling phenomenon that was verified experimentally and theoretiCally.