The synthesis of modified diketone ligands and the preparation of soluble Er3+ and Eu3+ tris-(beta-diketone)phenantroline complexes are described. The complexes, embedded in thin films of different conjugated and non-conjugated polymeric host matrices were studied by luminescence spectroscopy and used as active layers in organic light emitting single layer diodes to observe their characteristic emissions. The study of the optoelectronic properties of beta-diketo-complexes in a light emitting diode setup is presented.