The synthesis and characterization of gold nanoparticles (AuNPs-1) stabilized by a novel bifunctional thiolate organometallic complex containing Pt(II) centers, that is, trans,trans-[(CH(3)COS) (PBu(3))(2)Pt-C equivalent to C-C(6)H(4)-C(6)H(4)-C equivalent to C Pt(PBu(3))(2)(SCOCH(3))] (complex 1), has been carried out. As a comparison, gold nanoparticles stabilized with an organic thiol, allylmercaptane, that is, AuNPs-2, and self-assembled monolayers (SAMs) of both thiols were also prepared and investigated. The AuNPs-1 show a direct link between Pt(II) and Au nanoparticles through a single S bridge and are candidates for the achievement of 2D or 3D networks. The size control of the Au nanoparticles was achieved by careful control of synthesis parameters, and the hybrids were characterized by means of high-resolution transmission electron microscopy (HR-TEM) and synchrotron radiation induced X-ray photoelectron spectroscopy (SR-XPS). SR-XPS measurements allowed the assessment of the anchoring of the organic or organometallic thiols onto gold substrates as well as onto gold nanoparticles. AuNPs-2 with diameters in the range from 1.6 to 3.9 nm were obtained. AuNPs-1 with an average diameter in the range of 4.5-3.6 nm were obtained, and linkage between the nanoparticles can be envisaged with the formation of dyads supported by SR-XPS measurements. In fact, S2p core-level data indicate that both sulfur atoms of the organometallic thiol chemically interact with gold grafting vicinal natioparticles.