We have seen a surge of interest in metal organic frameworks (MOFs) over the past decades with more than 100,000 structures reported today. This interest is based on the modular building-block nature of their structure, which makes them tunable and widely applicable to many applications. Of particular interest is the storage, separation, and purification of gaseous fuels with MOFs as a much-needed alternative to the energy-intense processes currently in use. My talk will focus on results of a variety of MOFs that have been obtained by a close integration of synthesis, in situ vibrational spectroscopy, and ab initio materials modeling. In particular, we report on the development and characterization of four MOFs for the purpose of separating linear, mono, and dibranched alkane isomers through selective molecular sieving, which is of significant value in the petrochemical industry. The separation of such alkane isomers is a challenging and important industrial process for the production of premium gasoline, blending components with high research octane number. I will also show recent results that point towards non-standard kinetics in certain separation processes in MOFs as well as results for ultramicroporous MOFs that have the ability to effectively perform separations in the presence of water.