The title compound, C
18H
20ClN
3S, is a functionalized triazoline-3-thione derivative. The benzene ring is almost perpendicular to the planar 1,2,4-triazole ring [maximum deviation = 0.007 (1) Å] with a dihedral angle of 89.61 (5)° between them and there is an adamantane substituent at the 3-position of the triazolethione ring. In the crystal, N—H
S hydrogen-bonding interactions link the molecules into chains extending along the
c-axis direction. The crystal packing is further stabilized by weak C—H
π interactions that link adjacent chains into a two-dimensional structure in the
bc plane. The crystal studied was an inversion twin with a 0.50 (3):0.50 (3) domain ratio.