Metal-organic frameworks (MOFs) have attracted widespread attention for their porosity and applications in separation chemistry, catalysis, molecular sensing and gas storage. Mixed-ligand MOFs contain more than one type of ligand and offer the possibility of increased tailoring of structural features, such as chemical functionality or pore dimensions along particular directions. This talk will present a number of new MOFs constructed in our laboratory from commonly available ligands, which are often mixed-ligand MOFs, interpenetrated and show dynamic structural properties. Some of these MOFs are closely related in structure, in that they are isoreticular, yet show large differences in their thermal and sorption properties. In addition, an unexpected property of mechanical motion upon heating is revealed for one of the isoreticular MOF systems, a rare phenomenon for coordination polymers.