Metal-organic frameworks (MOFs) have come to the forefront over the past two decades because of their potential application in hydrocarbon separation under ambient conditions. MOFs are coordination polymers constructed by joining metal ions or metal clusters with organic linkers containing Lewis basic binding atoms. The main focus of the research pursued in this dissertation was to design and synthesize new metal-organic frameworks based on larger polycarboxyaryl linkers developed by our group. The linker design was as such to add a phenyl ring and an unsaturated C2 spacer to the analogous linkers based on linker expansion strategy. The aim of the linker design was to potentially increase the surface area, by virtue of the overall larger linker size, and afford higher adsorption energy to the hydrocarbon molecules (especially to the unsaturated hydrocarbons) owing to π(hydrocarbon)-π(linker) possibly chemisorptive stacking interactions, hence increasing their separations from impurities. To accomplish this goal, we reported several new MOFs and studied their separation abilities. We were also able to report MOFs for the capture of CO2 from industrial flue gases under ambient conditions.