The room-temperature (RT) synthesis of MCM-41 mesoporous compounds with high substitution levels of aluminium (Si/Al = 1.5) is achieved in a minimum time of synthesis. The compound shows similar characteristics to hydrothermally synthesized materials. Al-27 NMR study confirms the presence of tetrahedral aluminium in as-synthesized material as well as in the calcined material without observing the presence of octahedral aluminium after calcination.