In this work, we report combined experimental and theoretical studies on molecular structure, vibrational spectra, and NBO analysis of 4-(1-adamantyl)-5-[2-(3-hydroxynapthyl)]-2H-1,2,4-triazole-3(4H)-thione. The density functional theoretical computations were performed at B3LYP/6-311G+(d,p) levels to derive the optimized geometry, vibrational wavenumbers with FT-IR intensity, HOMO-LUMO energies, and several thermodynamic properties in ground state. H-1-NMR chemical shifts were also studied using gauge-including atomic orbital approach, which were found in good agreement with the experimental values. The delocalization of electron density various constituents of the molecule has been discussed with the aid of natural bond orbital analysis and the calculated HOMO-LUMO energies show that the charge transfer occurs within the molecule. Finally, the title compound was also evaluated for its in vitro anticancer activity against MCF-7 cancer line and inhibition activity of new 1,2,4-triazole with the protein BRCA2, is simulated by using AutoDock Vina software. Docking of synthesized compound against BRCA2, forget enzyme for MCF-7 cancer cell agent was achieved to explore the interactions of discovered hits within the amino acid residues of enzyme binding pocket.