Four trivalent Lanthanide complexes [Ln(2-Br-5-MOBA)3phen]2(Ln=Nd(1),Eu(2), Ho(3),Er(4))have been synthesized.The structure of 1-4 were established by single crystal X-ray diffraction.The complexes 1-3 were isostructural.Products 1-4 were also characterized by a series of techniques including the elemental analysis,IR and UV,XRD and TG/DSC-FTIR technology and so on.The study of thermogravimetric analysis indicated that complexes 1-4 were stabilized before 200 ℃.The processes of three-dimensional IR accumulation spectra of gaseous were amost the same with the steps of TG which could be both divided into four stages.The complex [Eu(2-Br-5-MOBA)3phen]2 emits strong and bright red fluorescence under UV at the room temperature and the fluorescence spectra of it containes three transitions: 5D0-7F0,5D0-7F1,and 5D0-7F2.Among all these transitions,the 5D0-7F2 at 621.4 nm is much stronger than the others,which speculates belong to the electric dipole transition of Eu3+ ion.