Method for purifying a crude of 2,5-furandicarboxylic acid (cFDCA) by crystallization is provided. The method includes (a) mixing the cFDCA and a solvent to form a mixture, wherein the solvent has a dipole moment of 3.7D (Debye) to 4.1D; (b) heating the mixture; (c) after step (b), cooling the mixture to precipitate a solid; and (d1) after step (c), filtering the mixture to collect a wet filter cake of the solid, and drying the wet filter cake to obtain purified FDCA. The purified FDCA has a higher FDCA purity than that of the cFDCA.