The title molecule, 3-{[4-(3-methyl-3-phenyl-cyclobutyl)-thiazol-2-yl]-hydrazono}-1,3-dihydro-indol-2-one (C 22 H 20 N 4 O 1 S 1 ), was prepared and characterized by 1 H NMR, 13 C NMR, IR, UV-visible, and single-crystal X-ray diffraction. The compound crystallizes in the monoclinic space group P21 with a ¼ 8.3401(5), b ¼ 5.6976(3), c ¼ 20.8155(14) Å , and b ¼ 95.144(5) . Molecular geometry from X-ray experiment and vibrational frequencies of the title compound in the ground state has been calculated using the Hartree-Fock with 6-31G(d, p) and density functional method (B3LYP) with 6-31G(d, p) and 6-311G(d, p) basis sets, and compared with the experimental data. The calculated results show that optimized geometries can well reproduce the crystal structural parameters, and the theoretical vibrational frequencies values show good agreement with experimental data. Density functional theory calculations of the title compound and thermodynamic properties were performed at B3LYP/6-31G(d, p) level of theory.