In the present paper, imidazo［5,6-f］ phenanthroline(IP), 2-aniline carbonyl benzoic acid (HAB) and 2-diphenylamine carbonyl benzoic acid(HDPAB) were synthesized at room temperature. Under the same condition, with HAB and HDPAB as the first ligand and IP as the secondary ligand, two novel ternary organic terbium complexes were prepared in ethanol solution. Elemental analysis demonstrated that the chemical formula of the two ternary complexes were Tb(HAB)3IP and Tb(HDPAB)3IP. The spectroscopic properties of the ligands and complexes were also discussed. IR spectra indicated that rare earth Tb3+ ion was coordinated with oxygen atoms of the first ligand HAB and HDPAB and two nitrogen atoms of the secondary ligand IP. The UV spectra showed that the main absorption was from the first ligand in the ternary complexes, the secondary ligand was bonded to rare earth Tb3+ ion and the energy transfer efficiency of HAB was higher than that of HDPAB. The excitation and emission spectra of the two terbium complexes were measured and investigated, especially by comparing their fluorescence intensities. Fluorescence spectra demonstrated that the two kinds of ternary organic terbium complexes could emit characteristic fluorescence of rare earth Tb3+ ion. But the fluorescence intensity of Tb(HAB)3IP was obviously higher than that of Tb(HDPAB)3IP. Compared with two first ligands HDPAB and HAB, the fluorescence intensities of the two ternary organic terbium complexes were found to be influenced by the molecule structure, and the benzene ring which was coordinated with nitrogen atom increased in HDPAB. In the system of ternary complexes, due to the different coordinated number of benzene ring, the mobility of electron and the distribution of electron cloud were changed. The variation affected the transition of the π electrons, which can take in the energy in ternary complexes. So, the energy transfer efficiency from the first ligand to rare earth Tb3+ ion decreased and Antenna effect achieved inefficiency in Tb(HDPAB)3IP.