This computational study focuses on the adsorption and diffusion of ethane and ethylene in IsoReticular Metal-Organic Frameworks (IRMOFs). We selected the IRMOFs family for the diversity of linkers, which allows understanding the effect that functionalized groups, ligand length, cyclic groups, or interpenetrating cavities has on the accessible pore volume of the structures and on the selective behavior towards the components of the mixture. At atmospheric pressure and 298 K, we found that the smaller interpenetrated structures (IRMOF-9, -11, and -13) exhibit larger adsorption selectivity than their non-interpenetrated counterparts (IRMOF-10, -12, and 14, respectively). Based on these findings we discuss the advantages of using interpenetrating structures for ethane capture. On the other hand, structures with large pore volume such as IRMOF-16 seem to reverse the adsorption selectivity in favor of ethylene.