The IZA and the hypothetical pure-silica zeolite structures are investigated theoretically to identify optimal dielectric materials for semi-conducting device applications. The dielectric constant, k, and the bulk modulus, B, are computed as second order energy-derivatives using a classical model. Six zeolites within the IZA database (JSR, IRR, OBW, BOZ, OSO, and NPT) exhibiting both ultra low-k (2.27, 2.33, 2.34, 2.37, 2.39, and 2.49, respectively) and relatively large bulk modulus are suggested as promising candidates. Finally, many hypothetical zeolite structures are predicted to outperform the aforementioned six structures, enhancing the pool of structures that can be used for low-k dielectric materials.