A single-crystal of (C18H18N3)Br-+(-), namely, 3-[(2-cyanophenyl)methyl]-1-propyl-1H-benzo[d]imidazol-3-ium bromide, was studied using X-ray diffraction techniques. This compound crystallizes in the triclinic space group P (1) over bar, with Z = 2, a = 8.9153(9) angstrom, b = 10.2681(8) angstrom, c = 10.6528(10) angstrom, and V = 858.69 (14) angstrom(3). Ions are linked by C-H center dot center dot center dot Br hydrogen bonds in the crystal. The geometrical parameters (bond length, and angles), the highest occupied molecular orbital energy, and the lowest unoccupied molecular orbital energy of this S2 molecule were calculated using the Spartan 10 program. The structural data were calculated by the density functional method using the ground state with the 6-311++G** basic set. Furthermore, a molecular docking analysis was performed to determine the binding mode in the active site of tyrosinase with S2 ligand.