Oxindoles and their derivatives have become an important compound on account of promising applications in medicine. Chlorine is found in azole group compounds used for fungal infections and is used in cancer chemotherapy drugs. In this study, the optimized molecular geometry, natural bond orbital (NBO) analysis, non-linear optical (NLO) properties and vibrational frequencies of chlorine-containing oxindole (6-chloro-2-oxindole) in monomer and dimer forms have been investigated using DFT/B3LYP/6-311++ G(d,p) method. The Hirshfeld surface and fingerprint analyses have been used to examine intermolecular interactions of the 6-chloro-2-oxindole compound. The reduced density gradient (RDG) analysis has been employed to investigate hydrogen bonding, Van der Waals interactions and the steric effect in the rings. The electronic properties and transitions for UV-Vis analysis have been calculated using the TD-DFT/B3LYP/6-311++G(d,p) method in monomeric and dimeric forms. The experimental spectral analysis of 6-chloro-2-oxindole has been investigated using UV-Vis, FT-IR and FT-Raman spectra. The antitumor activities of 6-chloro-2-oxindole with different receptors (3VNT, 3VHE and 5VZ2) have been performed by molecular docking analysis. Molecular docking calculations show the inhibitor effect against tyrosine kinase receptors. (C) 2021 Elsevier B.V. All rights reserved.