A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb(o-MBA)_3phen (where o-MBA =o-methylbenzoate and phen = 1,10-phenanthroline) was prepared from ethanol solution and its crystal structure was deter-mined by X-ray diffraction. The crystal of the complex Tb(o-MBA)_3phen belongs to triclinic crystal system and P 1 (#2)space group. The crystal data are as follows: a=1.4371(4)nm, b=1.7387(2)nm, c=1.3109(2)nm, α=96.37(1)°,β=107.21(2)°, γ=82.78(2)°, V=3.094(1)nm~3, Z=2, M_r=1489.12, D_c=1.598g·cm, μ=2.330mm~(-1) and F(000)=1488.00.The final R and R_w are 0.038 and 0.047 for 8668Π>2σ(Ⅰ)] unique reflections, respectively. In the complex each Tb~(3+) ion iseight-coordinated by one 1,10-phenanthroline molecule, one bidentate carboxytate group and four bridging carboxylategroups. The carboxylate groups are bonded to the terbium ion in two modes: the chelating bidentate and the bridging biden-tate. Excitation and luminescence data observed at room temperature show that the title complex emits A terbium o-methylbenzoate complex with 1,10-phenanthroline, Tb (o-MBA) _3phen (where o-MBA = o-methylbenzoate and phen = 1,10-phenanthroline was was prepared from ethanol solution and its crystal structure was deter- The crystal of the complex Tb (o-MBA) _3phen belongs to triclinic crystal system and P 1 (# 2) space group. The crystal data are as follows: a = 1.4371 (4) nm, b = 1.7387 (2) nm, c = 1.3109 (2) nm, α = 96.37 (1) °, β = 107.21 (2) °, γ = 82.78 = 2, M_r = 1489.12, D_c = 1.598 g · cm, μ = 2.330 mm -1 and F (000) = 1488.00. The final R and R_w are 0.038 and 0.047 for 8668Π> 2σ (I)] unique reflections , respectively. In the complex each Tb ~ (3+) ion iseight-coordinated by one 1,10-phenanthroline molecule, one bidentate carboxytate group and four bridging carboxylate groups. The carboxylate groups are bonded to the terbium ion in two modes: the chelating bidentate and the bridging biden-tate. Excitation and luminescence data observed at room temperature show that the title complex emits