A modified retrograde crystallization process with the circulation of supercritical carbon dioxide has been designed and tested for the separation of a mixture containing two solids. The apparatus consists of an extractor and a crystallizer, which are kept at different temperatures but at a fixed pressure within the crossover region. The metastable zone within the crossover region of the ternary system is first determined. Separation experiments are then conducted under various conditions with the crystallizer temperatures within or slightly above the metastable zone. The benzoic acid/1,10-decanediol/CO2 system with a wide crossover region represents an ideal example of the modified process, and the results show that it is possible to obtain essentially pure products of both components (> 97 wt%) from a 50/50 wt% mixture of benzoic acid and 1,10-decanediol. The average recovery is 49.3% for benzoic acid and 85.8% for 1,10-decanediol. The other system of 2,3-/2,6-dimethylnaphthalene/CO2 with a narrow crossover region is then analyzed to demonstrate the possibility for the separation of organic isomers, and the results show that the modified process can produce the 2,6-dimethylnaphthalene of almost 100 wt% purity with a recovery of 37.1% starting from a mixture of 50/50 wt% isomers.