Abstract: Neutral lanthanide(III) complexes including at least one ligand are disclosed. The ligand includes a heterocyclic aromatic ring with at least one carboxylic acid group attached thereto, wherein a heteroatom of the heterocyclic ring and the carboxylate function of the carboxylic acid group co-ordinate (chelate) to the lanthanide. The complexes can be used in luminescent lamps and luminescent displays. The complexes can be synthesized by heating a mixture of a lanthanide 3+ salt and ligand L in a suitable solvent until a precipitate of the lanthanide complex forms. In one embodiment, the formal 3+ charge on the lanthanide is neutralized by providing in the ligands for the complex, three coordinating carboxylate groups, (RCO2?). The heteroatom coordinated to the lanthanide may be nitrogen, oxygen, sulfur or phosphorus.