Porous and composite metal/polymer nanowires of controllable composition and shapes have been prepared by dealloying gold-silver alloy nanowires and backfilling the resulting pores with an electropolymerized polypyrrole before dissolving the membrane template. The composition, shape and properties of the new porous and composite nanowires can be rationally controlled by tuning the composition of the initial alloy nanowires. The volume fraction of the polymer in the composite nanowires increases upon increasing the silver content in the initial alloy. The new membrane template preparation route is versatile and could be extended to diverse composite nanowires, based on different polymers and metals, indicating great promise for wide range of applications. The preparation of porous polymeric nanowires, based on acidic (HBr) removal of the gold component of the composite, is also illustrated. We will also describe barcoded alloy nanowires, with high coding capacity, for simplified tagging and idenitfication purposes.