N-alkyl-substituted imidazolidine-2-thiones act as monodentate ligands coordinating through sulfur. The gold(I) complex, chloro(N-propyl-1,3-imidazolidine-2-thione)gold(I), [(PrImt)AuCl] crystallizes in the monoclinic space groupC2/cwitha=10.164(4),b=14.836(2),c=13.590(9)A, β=95.08(5)° andZ=8. The X-ray structure determined using intensity data collected on a CAD4 diffractometer and refined by full-matrix least-squares methods, converged to a conventionalRfactor value of 0.077 for 1153 observed reflections. Gold(I) has a linear coordination with an S-Au-Cl angle of 173.3° and Au-S and Au-Cl distances of 2.26(1) and 2.27(1)A. The13C nmr spectra of the complexes indicated a high-field shift of about 8 ppm for the C-S carbon, suggesting identical coordination sites in the solid and solution states. This large shift in13C resonance can be used as a diagnostic nmr observation for location of coordination sites in solution of these and other C-S bonded complexes.