Recently, amine-functionalized mesoporous silica materials have attracted considerable attention as a promising chemical sorbent for postcombustion CO2 capture applications. However, the grafting of amines in the conventional MCM-41 support induces the subsequent reduction of surface area and pore volume of the sorbents, affecting the CO2 adsorption-desorption kinetics significantly. To mitigate this problem, expensive pore expansion agents have been used to increase the pore size as well as the pore volume. The present study provides an innovative approach to the development of novel pore-expanded MCM-41 without the application of any swelling agent. The average pore size (similar to 30 nm) obtained in our work is remarkably higher than the values (9 to 10 nm) reported in the literature. On the basis of the fundamental understanding of micelle properties under different alkaline conditions, a mechanism for the pore expansion process is proposed. The outcome (1.2 mmol/g) of the preliminary CO2 adsorption studies carried out on the novel support material grafted with monoamine silane is very promising.