The photoluminescent （PL） and electroluminescent （EL） properties of a series of ligand emitting rare earth complexes (including Y3+, La3+, Gd3+ and Lu3+) were systematically studied. These complexes have the same anionic ligand, 1-phenyl-3-methyl-4-isobutyryl-5-pyrazoloneate （PMIP）, and three neutral ligands, triphenyl phosphine oxide （TPPO）, 2, 2′-dipyridine （Bipy） and phenanthroline （Phen）. Measured with 60 nm thin film of these complexes vaporized in vacuum on quartz substrates, a good regularity in the PL properties was observed. For rational comparison, the same structural EL devices based on these complexes, ITO/PVK （40 nm）/the complex （80 nm）/Mg: Ag （200 nm）/Ag （100 nm）, were fabricated. Excluding the exciplex emission happens, the EL luminance usually increases with the increasing of PL efficiency.
