The objective of this proposed program is to rationally develop solubility-selective mixed matrix membranes (MMMs) comprising highly polar rubbery polymers and soluble metal-organic polyhedra (MOPs) to achieve high carbon dioxide (CO2) permeance (3,000 gas permeation units [GPU]), high CO2/nitrogen (N2) selectivity (75), and CO2/oxygen (O2) selectivity (30) at 60°C. Such membranes would outperform currently leading membranes by 50 to 100%, which can be implemented into Membrane Technology and Research Inc.’s (MTR’s) membrane processes and may enable CO2 capture at less than $30/ton CO2 from coal power plants.