Methods of forming mesoporous zeolites with tunable pore widths are provided. In some embodiments, the method includes mixing a silicon-containing material, an aluminum-containing material, and at least a quaternary amine to produce a zeolite precursor solution. The zeolite precursor solution is pre-crystallized at a pre-crystallization temperature of greater than 125° C. and autogenous pressure to form a pre-crystallized zeolite precursor solution and combined with an organosilane mesopore template to produce a zeolite precursor gel. The zeolite precursor gel is crystallized without a previous discrete functionalization step to produce a crystalline zeolite intermediate and the crystalline zeolite intermediate is calcined to produce the mesoporous zeolite. An organosilane mesopore template in accordance with is also provided, where R is an aliphatic, aromatic, or heteroatom-containing group.