The title compound, C12H11N3S, contains an intramolecular N3-H...N-py hydro
gen bond, which stabilizes the coplanarity of the thiourea moiety and the p
yridine (py) ring. The molecules form centrosymmetric hydrogen-bonded dimer
s, with the S atom forming bifurcated intermolecular hydrogen bonds involvi
ng the N2-H group of the thiourea moiety and the C3-H group of the pyridyl
ring.