Reduction of the dielectric constant k to the ultra low-k range is important for the continuing miniaturization of semiconductor devices. It is demonstrated that gamma-cyclodextrin can act as an effective porogen (see Figure) to reduce k while maintaining good film strength. A continuous thin pure-silica zeolite MFI film with k = 1.8 and elastic modulus of 14 GPa is reported, prepared by spin-on from a zeolite nanoparticle suspension.