Multiple silver(I)-aurates(I) have been prepared by salt metathesis reactions that act as efficient single-source precursors to colloidal gold silver alloys with the highest possible atom economy in the chemical synthesis of nanostructures. The CF3 group present on the Au cation acts as an in situ reducing agent and can be converted into CO ligands by simple hydrolysis. This ligand-mediated activation and subsequent decomposition of metalorganic precursors impose a molecular control over the nucleation process, producing homogeneously alloyed (AgAu) nanoparticles with an atomic Au:Ag ratio of 1:1. The concept also works for the AuCu system and acts as a pointer to replace Au (Ag) with less expensive (Cu) metals.