Herein, we demonstrate a facile approach to manganese-doped highly ordered mesoporous silicate with oxidation-suppression function. As biocompatible supports of guest ions, the ordered mesoporous silicate was synthesized by evaporation-induced self-assembly. The phase-transition from disordered to lamellar structures in the highly ordered mesoporous structure of these porosity-tuned materials was controlled by adjusting the concentration of a lab-made polystyrene-b-polyethylene oxide copolymer. Manganese was successfully incorporated as a guest in the hexagonally packed mesoporous silicate by using an ultrasound-assisted technique. The incorporation of manganese ions into the pores of a mesoporous silicate support could be induced for host–guest functional applications. Manganese-doped mesoporous silicate structures have been examined for their use as antioxidizing agents by electron spin resonance (ESR) measurements and radical-scavenging tests. The manganese atoms in the mesoporous structures could act in a free-radical-scavenging capacity, much like manganese nanoparticles. The high efficiency of their oxidation-suppression function is extended for application to catalytic products.