In this work, the solidliquid equilibrium of 4-(bromomethyl)-2(1H)-quinolinone in methanol, ethanol, n-propanol, isopropanol, n-butanol, acetonitrile, 1,4-dioxane, toluene, 2-butanone, dimethylformamide (DMF), n-methyl pyrrolidone (NMP), and dimethyl sulfoxide (DMSO) within the temperature range from 273.15 to 313.15 K was studied. The solubility of 4-(bromomethyl)-2(1H)-quinolinone was the highest in DMSO and the lowest in toluene at all studied temperatures. As expected, the solubility of 4-(bromomethyl)-2(1H)-quinolinone increased with an increase in temperature in the 12 tested solvents. At 313.15 K, the mole solubility of 4-(bromomethyl)-2(1H)-quinolinone was ranked in the following order: DMSO (3.81 x 10(-2)) > NMP (1.426 x 10(-2)) > DMF (8.28 x 10(-3)) > 1,4-dioxane (1.37 x 10(-3)) > 2-butanone (7.92 x 10(-4)) > n-butanol (5.58 x 10(-4)) > n-propanol (4.76 x 10(-4)) > ethanol (3.85 x 10(-4)) > isopropanol (3.60 x 10(-4)) > methanol (3.03 x 10(-4)) > acetonitrile (2.23 x 10(-4)) > toluene (0.56 x 10(-4)). The acquired solubility data of 4-(bromomethyl)-2(1H)-quinolinone in the studied solvents were correlated using the modified Apelblat equation and the lambda h equation. The maximum value of the relative average deviation (RAD) was 3.44%, and all values of RAD in the modified Apelblat equation were smaller than those in the lambda h equation; therefore, the modified Apelblat equation is more suitable to correlate the results. The obtained solubility and thermodynamic studies would be very helpful for optimizing the purification process of 4-(bromomethyl)-2(1H)-quinolinone.