We report the formation of monomeric and aggregated tetrakis(p-sulfonatophenyl)porphyrin encapsulated within an aluminosilicate mesostructure, specifically MCM-41, under different pH conditions. It was necessary to stabilize the synthesized MCM-41 through use of a silylation reagent, (aminopropyl)triethoxysilane, which cross-links oxygen on the surface (thus rigidifying the walls of the mesoporous material) and functionalizes the interface for proper guest-host interaction. XRD, UV-vis absorption, and fluorescence measurements are used as spectroscopic tools to characterize the various products.