In this work, we report a simple approach for controllable synthesis of one-dimensional (ID) gold nanoparticle (AuNP) assemblies in solution. In the presence of divalent metallic ions, poly(acrylic acid)-1-dodecanethiol-stabilized AuNPs (PAA-DDT@AuNPs) are found to form I D assemblies in aqueous solution by an ion-templated chelation process; this causes an easily measurable change in the absorption spectrum of the particles. The assemblies are very stable and remain suspended in solution for more than one month without significant aggregation. The morphologies of these I D assemblies are dependent on the concentration of metallic cations in the solution. While lower concentrations led to the formation of particle dimers, higher concentrations generated long nanoparticle chain networks. In addition, the effect of EDTA, the solution pH, and the size of the PAA-DDT@AuNPs is also studied for further exploration of the mechanism of the formation of the I D assemblies.