Although progress has been made in the construction of single-electron devices (SEDs), few of the reported approaches have proved practically applicable, mainly owing to their cost-ineffectiveness and need for sophisticated instrumentation. Herein, a conceptually new method for fabricating SEDs through the metallization of divalent DNA-nanoparticle conjugates is described. Specifically, divalent DNA copolymers that are conjugated to gold nanoparticles (AuNP) were synthesized by application of the enzymatic extension of DNA conjugated on quantum-sized AuNPs. This conjugate structure allows the distance between the resulting poly(dG)-poly(dC) and the AuNP to be controlled by an ssDNA spacer. To afford poly(dG)-poly(dC) sequence-specific metal deposition, Cisplatin capable of specific chemisorption on the poly(dG)-poly(dC) is incubated with the divalent DNA copolymer–AuNP conjugates, followed by reduction of the Cisplatin to Pt metal at base resolution. As a result, AuNPs separated from the Pt “electrodes” by the ssDNA barriers in a single conjugate could be created as a double-tunnel junction for SEDs. This study is thought to be an important step toward the programmable organization of DNA for use in SEDs.