The 2-(4-ethoxyphenyl)isoindoline-1,3-dione has been synthesized and characterized by X-ray single-crystal diffraction. The compound crystallizes in the orthorhombic sp. gr. Pna2(1) with four molecules in the unit cell and one molecule in the asymmetric unit. The molecular structure is not planar. The dihedral angle between the isoindoline and phenyl rings is 55.69(7)degrees. In the crystal structure, molecules are linked together by intermolecular C-HO hydrogen bonds.