Due to its low volumetric energy density adequate storage of hydrogen is currently a key issue in hydrogen economy. Rationally designed microporous metal organic frameworks (MMOFs) might be a promising candidate for H₂ storage. As the pore shape and size of the MMOFs can be modified, they might also be suitable for use in gas separation. In this presentation, we report the design and synthesis of two new isostructural MMOFs, [M₃(ndc)₃(ted)]∙nDMF (M = Co, Ni, ndc = 2,6-naphthalenedicarboxylate, and ted = triethylenediamine). The crystal structures and pore properties of these compounds are characterized, and their storage and separation capability at different temperatures for gases of various sizes such as hydrogen, water, ethanol, n-hexane, benzene and 1,3,5-trimethylbenzene(TMB) will be discussed.