In this study, the chemical structure of 2,4-dihidroksibenzaldehit Sülfisoksazol (S2M-S3) was tried to be elucidated by 1H-NMR and 13C-NMR and FT-IR spectroscopic methods. As a result of the calculations, it was seen that the theoretical values were compatible with the experimental values. In addition, HOMO-LUMO molecular orbital energies, nonlinear optical properties (NLO), molecular electrostatic potential (MESP) of S2M-S3, Cu(S2M-S3)2 and Pd(S2M-S3)2 compounds were investigated. As a result of the calculations, the energy band gap between the HOMO and LUMO orbitals as 4.09 eV and first static hyperpolarizability as 27677.7×10-33 esu were calculated for S2M-S3. All calculations were made at the DFT / B3LYP / 6-311 ++ G (d, p) level of theory and performed with Gaussian 09 and Gauss View 5.0 package programs.