The first system, ZIF-7 (Figure ), has previously been reported by a number of groups and used for gas separation, solid-phase extraction, and membrane filtration. Here we adapted a method developed by Liu et al. and Peng et al. for its synthesis. Benzimidazole and zinc nitrate hexahydrate were reacted under ambient conditions in DMF to produce a 3D ZIF-7-I phase material prior to refluxing in water to induce a hydrothermal phase transition that resulted in the bulk layered phase, ZIF-7-III (Figure ). X-ray powder diffraction (XRPD) pattern of the resulting white microcrystalline powder matched that of the predicted ZIF-7-III pattern (Figure ) while scanning electron microscopy (SEM) studies also confirmed the formation of the layered material (Figure ).