Efficient luminescent materials in solution, powder, or thin-film form are made here by combining poly(ethylene glycol) (PEG), terpyridine, and metal cations. Strong green emitters with a luminescence yield as high as 0.63 are reported for terpyridine-metal ion complexes suspended in liquid PEG. Evidence is presented that the structure of the luminescence spectrum is independent of the metal ion used, while luminescent lanthanides completely lose their emission characteristics. In contrast, solid ternary lanthanide-terpyridine-PEG complexes display emission characteristic of the lanthanide ion.