The synthesis and characterization of oligothia dendrimers and their use for the formation of gold nanoparticles is described. The role played by these dendrimers in controlling the stability and size of the particles is discussed. It is shown that the generation of the dendrimers, as well as the position of the sulfur atoms in the dendritic structure (S6G1 and S9G1), influence the formation and reactivity of the nanoparticles. UV-visible spectroscopy, 1H nuclear magnetic resonance spectroscopy and high-resolution transmission electron microscopy have been employed for the characterization of the nanoparticles. Furthermore, purification by Soxhlet extraction has been performed.