An investigation into the ability of the ambidentate, "extended-reach" ligand 1-(4'-pyridyl)pyridin-4- one (pypyd) to form polymeric network complexes has resulted in the X-ray characterization of the compounds [Cu(pypyd)(2)-(H2O)(2)](ClO4)(2). pypyd 1, [Co2Dy2(pypyd)(8)(H2O)(2)(NCS)(4)(NO3)(4)][Co(NCS)(4)] 2, and [NiYb(pypyd)(4)(NCS)(2)(NO3)(2)]-(NO3) 3. The homometallic copper complex, 1, forms a (4,4) sheet polymer with additional intrasheet crosslinking via hydrogen bonding of noncoordinated pypyd molecules to the aqua ligands on the Cu centers. The heterometallic Co/Dy complex, 2, also produces a contiguous (4,4) sheet but without the hydrogen bonded pypyd cross-link. The heterometallic Ni/Yb compound, 3, forms a more complex array comprised of mutually interpenetrating networks each of three-dimensional (6,4) topology. The crystal structure of an acetic acid adduct of pypyd, 4, is also reported.