The low-temperature transformation of CO₂ and CH₃OH into dimethyl carbonate (DMC) represents a sustainable and low-carbon pathway for producing essential chemicals. An ideal energy-efficient catalysis necessitates a catalyst capable of facilitating interactions between the simultaneously activated CO₂ and CH₃OH. Herein, we designed the spatially proximate In₅ and In₄₊₁···_ּIn₄ sites on the In₂O₃ surface, enabling efficient DMC synthesis from CO₂ and CH₃OH below 100 °C. The In₅ sites are responsible for CH₃OH adsorption; while CO₂ adsorbs on the In₄₊₁···In₄ pairs through interactions between its O atom with two In sites, as well as between the C atom and a lattice O atom. Furthermore, the spatial intimacy of In₅ and In₄₊₁···In₄ sites, with a distance of ~ 4.7 Å, facilitate direct interaction between the adsorbed CO₂ and CH₃OH. By optimizing oxygen vacancies, porous In₂O₃ nanocubes with abundant dual-active sites achieved a DMC generation rate of 8.1 mmol·g_cat⁻¹·h⁻¹ at 100 °C, significantly surpassing previously reported catalysts. These findings demonstrate a promising route for the energy-efficient DMC synthesis from CO₂ and CH₃OH.