We report the successful metal salt complexation of ultrathin terpolymer films spin-coated onto glass and silicon substrates as well as the subsequent reduction of the salt to metal clusters. The photolabile polymer consists of a diazosulfonate side chain polymer which may be decomposed under UV irradiation. All stages, i.e., initial, complexed, and reduced stage, are characterized using optical transmission spectroscopy and X-ray photoelectron spectroscopy. The film surface roughness, morphology, and thickness are determined by atomic force microscopy and ellipsometry. On one hand, our experiments show that nonirradiated diazosulfonate side groups complex with silver acetate provided from solution and that silver ions chemically reduce when exposed to a sodium borohydride solution. On the other hand, the complete destruction of the photolabile diazosulfonate unit under UV irradiation is proven. Our experimental investigations are the first successful efforts demonstrating the selective metallization of deposited ultrathin diazosulfonate polymer films.