We demonstrate that supermolecular templating allows tuning the pore size of ordered mesoporous materials in the once elusive range from 30 nm to more than 60 nm through simple control of synthetic variables (salt/supermolecule concentration and hydrothermal temperature). Gold nanoparticles (AuNPs) within the extra-large pores exhibit dramatically increased lifetime compared to those located within relatively small mesopores due to the enhanced mass diffusion that suppresses coke deposition on AuNPs.