A new approach to one-dimensional organization of gold nanoparticles (2–4 nm) is described, using poly(4-vinylpyridine) (P4VP) molecular chain as a template with the mediation of free Cu²⁺ ion coordination. The assembly was conducted on freshly prepared mica surfaces and in aqueous solution, respectively. The surface assembly was characterized by tapping mode atomic force microscopy (AFM), observing the physisorbed molecules in their chain-like conformation with an average height of 0.4 nm. By the mediation of Cu²⁺ ions, gold nanoparticles modified by 3-mercaptopropionic acid were deposited onto the molecular chains, evidenced by a clear increase in height. Generation of the network in solution is time-dependent and pH reversible, characterized by UV–vis absorption spectra and transmission electron microscopy (TEM). No comparable network is obtained without Cu²⁺ ions, indicating the significance of ionic mediation. A mechanism for the self-assembly in solution is proposed, and the nature of the mediation of Cu²⁺ ions was identified by x-ray photoelectron spectroscopy (XPS).