Abstract The chemical conversion of CO 2 to long‐chain chemicals is considered as a highly attractive method to produce value‐added organics, while the underlying reaction mechanism remains unclear. By constructing surface vacancy‐cluster‐mediated solid frustrated Lewis pairs (FLPs), the 100 % atom‐economical, efficient chemical conversion of CO 2 to dimethyl carbonate (DMC) was realized. By taking CeO 2 as a model system, we illustrate that FLP sites can efficiently accelerate the coupling and conversion of key intermediates. As demonstrated, CeO 2 with rich FLP sites shows improved reaction activity and achieves a high yield of DMC up to 15.3 mmol g −1 . In addition, by means of synchrotron radiation in situ diffuse reflectance infrared Fourier‐transform spectroscopy, combined with density functional theory calculations, the reaction mechanism on the FLP site was investigated systematically and in‐depth, providing pioneering insights into the underlying pathway for CO 2 chemical conversion to long‐chain chemicals.