The one-dimensional, polymeric compound C15H11N3)Eu(H2O)(2)(NO3)(Pt(CN)(4)) center dot CH3CN (1) has been shown to display an efficient donor-acceptor intramolecular energy-transfer (IET) process where ligand donors transfer energy to the Eu-III acceptor. Single-crystal X-ray diffraction has been used to investigate the structural features of this compound in order to help understand the observed IET process. Crystallographic data: 1, monoclinic, space group P2(1)/c, a = 12.835(1) angstrom, b = 15.239(1) angstrom, c = 13.751(2) angstrom, beta = 105.594(9)degrees, V = 2590.8(5) angstrom(3), and Z = 4 (T = 290 K).