The continuing evolution of microprocessors requires the timely development of low-dielectric constant (low-k) materials. Pure-silica-zeolite MEL has been shown to be a good ultra low-k material due to its intrinsically uniform pore size distribution, high hydrophobicity, strong mechanical properties and chemical stability. Our group's previous work has employed a two-stage synthesis method to synthesize an MEL nanoparticle suspension to prepare spin-on films. With this method, both particle size and nanocrystal yield of zeolite suspension increase with respect to the synthesis time. While higher yield gives the material a lower k value, larger crystals will introduce complications from the spin coating process, such as increased surface roughness, surface striations, large mesopores, and electrical breakdown. In this study, the two-stage synthesis has been modified into an evaporation-assisted two-stage synthesis method by adding a solvent evaporation process between the two thermal-treatment steps. The prepared nanoparticles from the evaporation-assisted two-stage synthesis have smaller particle sizes and the synthesis yield is held the same. The 60% solvent-evaporated suspension shows a bi-modal particle size distribution and the primary nanoparticles around 14 nm are stable in the final suspension. Increase of concentration, pH value and viscosity after evaporation are responsible for the decrease in particle size. The spin-on films prepared from the three-stage synthesis suspension contain fewer striations and show better mechanical property comparing with the two-stage synthesis suspension films while maintaining the same k values.