- We demonstrate the overgrowth of Au on CdSe nanowires with control over Au crystal morphology upon increasing addition of Au precursor. Extending this overgrowth technique to catalytically active metals and binary metal systems (Pt, PtCo, and PtNi) exemplifies the broader range of these metal− semiconductor hybrid nanomaterials. Structural and compositional characterization was carried out by low-and high-resolution TEM, EDS analysis, and XRD. Magnetic characterization of the PtCo binary metal hybrid systems was conducted using SQUID magnetometry. Changes in the optical properties of the decorated materials compared to the as-made CdSe nanowires confirm the presence of electronic coupling at the metal− semiconductor interface, an important material property for photocatalytic applications.