  We study molecular nanostructures on the surface of a d_(x2-y2)-wave
superconductor. We show that the interplay between the molecular
nanostructure's internal excitation spectrum and quantum interference of the
scattered host electrons leads to a series of novel effects in the local
density of states. We demonstrate that these effects give insight into both the
nature of the superconducting pairing correlations and of the intermolecular
interactions.
