We show a route to produce a two- and three-dimensional network of nanoparticles via polymer-mediated self-assembly. A negatively charged polymer, CO2-functionalized poly (para-phenyleneethylene) (PPE-CO2), is used to build this network of iron-platinum (Fe-Pt) nanoparticles. The nanoparticles arrange locally in hexagonal and cubic lattice type network structures. The size and form of the networks are characterized with atomic force microscopy (AFM), transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS), and grazing incidence small-angle X-ray scattering (GISAXS). In thin film the network is perturbed due to the force field acting during spin coating.