(+)-2-Thionosparteine was obtained for the first time. 1H and 13C NMR spectroscopy were used for quantitative determination of conformational equilibrium in solution. The X-ray structure revealed two molecules in the asymmetric unit that differ substantially in their conformations. Weak C- H···S interactions are characterized and compared with the intramolecular hydrogen bond C-H···O in the crystal structure of 2-oxosparteine.