2-(4-Ethoxyphenyl)isoindoline-1,3-dione molecule has been characterized by experimental FT-IR and UV-visible spectroscopic methods. Density factional theory calculations of the molecular structure and vibrational spectra have been performed using the B3LYP/6-311++G(d,p) level of theory for the 2-(4-ethoxyphenyl)ignndoline-1,3-dione. The theoretical results arc compared with the experimental observations. Using the TD-DFT methodology, the electronic absorption spectra of the investigated molecule have been calculated. The enthalpy, entropy and heat capacity properties based on the vibrational calculations are calculated at different temperatures. Besides, the frontier orbitals, atomic charges, reactivity descriptors, molecular electrostatic potential, interaction energies and nonlinear optical properties are predicted by the density functional theory calculations.