The Supercritical Fluid Research Center at the National Institute of Advanced Industrial Science and Technology (AIST) has made a major advance in the practical application of carbon dioxide fixation for cyclic carbonate production, using a two-phase reaction system combining supercritical carbon dioxide and ionic fluid devised by the Research Center. The team has successfully developed a rapid synthesis method that can be used under moderate reaction conditions. The supercritical carbon dioxide + ionic fluid method rivals the conventional phosgene method in terms of synthesis capabilities. Over the past few decades, researchers around the world have tested various reaction systems and catalysts for carbon dioxide fixation, with a view to applying this to cyclic carbonate synthesis. To date, no method has been discovered that is superior to the phosgene method in terms of reactivity. The development of the supercritical carbon dioxide + ionic fluid method is expected to significantly accelerate the development of production methods for more environmentally friendly engineering plastics.