The enhancement of CO2 capture due to the confinement of polar molecules within InOF-1 was previously demonstrated. In particular, the presence of MeOH produced 1.30-fold increase in the total CO2 capture. This was explained before with the presence of hydrogen bonds. However, a detailed analysis of the hydrogen bonds among μ2-OH functional groups, MeOH molecules and CO2 molecules was not elucidated; moreover, the possible mechanisms that could explain the enhancement of the capture were also not explained. In this investigation, the density functional theory (DFT) periodic calculations and experimental in situ DRIFTS results allowed us to postulate four plausible CO2 adsorption mechanisms for MeOH-functionalised InOF-1, which described the hydrogen bonds and rationalised the nature of the CO2 capture enhancement.