Two new binuclear (europium and lanthanum) b -diketone complexes Eu0.9La0.1(TTA)3Phen and Eu0.5La0.5(TTA)3Phen in which Phen is 1,10-phenanthroline, TTA is an anion of thenoyltrifluoroacetone (HTTA) were synthesized for the first time. They showed intense photoluminescence (PL) and mechanoluminescence (ML), and had their maximum PL and ML spectra peaked at 613.5 nm with half bandwidth of 10 nm respectively. Their PL and ML intensity were obviously stronger than these from Eu(TTA)3Phen. It is considered that binuclear (europium and lanthanum) b -diketones complexes are promising ML and PL materials.