The solubilities of sebacic acid in mixed solvents n-propanol + water have been measured by a dynamic method using a laser monitoring observation technique over a temperature range (288 to 35 1) K. A synergistic effect on solubility was found to occur in sebacic acid + n-propanol + water mixed systems. To detect the synergistic effect, solubilities of sebacic acid in 14.35 %, 36.97 %, 79.81 %, and 90.00 % mole fraction ethanol aqueous solution were determined to supplement our previous report. A weak synergistic effect was found for sebacic acid + ethanol + water mixed systems. The solid-liquid equilibrium (SLE) data have been fitted using the lambda h equation, the Wilson equation, and the NRTL equation. The comparison between the experimental and the calculated solubilities for the three models is reasonable, and the root-mean-square deviations for each system range from (0.30 to 1.95) K.