A novel 3D metal-organic coordination polymer constructed from hollow, spherical, nanometer-sized molecular faceted polyhedra and a flexible tetracarboxylate ligand designed to simultaneously assemble and cross-link these nanoballs in situ has been synthesized and structurally characterized. The crystal structure involves 2-fold interpenetration with each framework exhibiting pores of dimensions which vary from less than 1 nm to just over 2.5 nm.