Communication: Single crystal Ag nanorods and elegant highly ordered dendritic supramolecular nanostructures (see Figure) of Ag nanoparticles have been prepared via a novel ultraviolet photoreduction technique at room temperature using poly(vinyl-alcohol) (PVA) as protection agent. The concentration of both the PVA and AgNO3 play a significant role in the growth of the nanorods and dendrites.