Poly(ether carbonate)s (PEC) and poly(ether ester)s (PEE) were synthesized by step growth polymerization, and the reaction conditions were optimized. The solubility of the polymers in CO2 was then evaluated using two methods: (i) observation of the cloud point and (ii) gravimetric extraction. Our results suggest that it is difficult to give an exact description of the solubility profiles for these polymers using cloud points alone, particularly in cases where there is a broad distribution of molecular weights. We suggest that the cloud point data are more easily interpreted in combination with a quantitative gravimetric extraction method that we have developed. It was found that the CO2 solubility of the PEC and PEE samples was strongly affected by both the polymer molecular weight and the chemical structure.