Highly crystalline vertically aligned Ag2S/CdS heterostructured nanosheets with lateral sizes of several micrometers and thicknesses of a few nanometers are prepared directly on silver surfaces by a two-step process. Firstly, Ag2S sheets were prepared by direct reaction of partially dissolved elementary sulfur in methanol with a solid silver surface in methanol at room temperature. The second step involves a self-limited cation exchange of Ag+ vs. Cd2+ to achieve the formation of large-area Ag2S/CdS heteronanosheets on the solid substrate. The cation exchange was proven and investigated over time via several analytical methods, e.g. X-ray diffraction, Raman spectroscopy and three-dimensional photoluminescence mapping.