Hierarchical mesoporous silicoaluminophosphate (M-S-34-N) was assembled for the first time in the presence of ammonium hydroxide as the base. The resulting materials were subsequently stabilized via vapor-phase treatment in presence of tetraethylorthosilicate (TEOS). N-2 sorption analysis and pyridine desorption studies revealed that materials possess uniform mesoporous channel with high surface area, large pore volume, and strong Lewis acidity, respectively. The local environment of aluminum and silicon were followed with solid-state Al-27, and Si-29 MAS NMR spectral studies, which indicates their successful framework incorporation. The strong acidity present on the resultant M-S-34-N-VPT facilitates for liquid-phase trans-alkylation of naphthalene using 1,3-diisopropylbenzene.