Colloidal gold particles synthesized in water have been capped with octadecanethiol (ODT) molecules rendered water-soluble by threading with alpha -cyclodextrin (alpha -CD) molecules. Thereafter, the gold nanoparticles could be transferred into an organic solvent such as chloroform by vigorous shaking of a biphasic mixture of the alpha -CD-threaded ODT-stabilized gold hydrosol and: chloroform. The phase transfer of the gold : nanoparticles could be observed as a rapid transfer of color from the aqueous phase to the organic phase. During shaking of the biphasic mixture, it is believed that alpha -CD molecules are dislodged from the octadecanethiol molecules, rendering the gold particles hydrophobic and amenable to phase transfer. Transmission electron microscopy studies of films of the gold nanoparticles in chloroform formed by solvent evaporation indicate a uniform size distribution of the nanoparticles and hexagonal close-packing of the particles in the film.