Synthetic, spectroscopic (LR, Raman, NMR, APCI-MS), and X-ray crystallographic studies demonstrate that the highly favorable thiolation of bismuth can be controlled by manipulating stoichiometric conditions for the reactions of BiCl3 or Bi(NO3)(3) With aminoethanethiolate anions. With this approach, the first homologous series of mono-, bis-, and tris-thiolated bismuth complexes has been isolated and comprehensively characterized, which includes tris (aminoethanethiolato)bismuth(III) (1), bis (aminoethanethiolato) bismuth(III) nitrate (2NO(3)), and bis(aminoethanethiolato)bismuth(III) chloride (2Cl), the corresponding dimethylaminoethanethiolato derivatives (1(Me) and 2(Me)Cl), and dimethylaminoethanethioiatobismuth(III) chloride (3(Me)). The acyclic dimethylammoniumethanethiolatobismuth(III) chloride (4(Me)) extends the series and represents decoupling of the amine by protonation with retention of monothiolation. The synthetic guidelines are likely to be generally applicable to other metals and other asymmetric ligands.