This Communication describes a novel adenine-pyrene conjugate (1) and its solid-state structure with silver and copper ions. Singlecrystal studies of metal complexes of 1 offer insight into molecular interactions and provide a basis to rationalize possible interactions in the solution state, leading to excimer formation. The robust nature of this interaction was further confirmed by deposition of the silver complex on a graphite surface, which exhibited a remarkable resemblance to its solid-state structure. The structural basis of selective excimer formation in the presence of Ag+ ions presents a viable approach for ratiometric detection of these ions. © 2010 American Chemical Society.