3,4-thiophenedicarboxylic acid (3,4-H2tdc) as the first ligand, 1,10-phenanthroline (phen) as the auxiliary ligand, three complexes Ln2(Htdc)2(tdc)2(phen)2(H2O)4(Ln=Eu 1, Gd 2, Tb 3) were synthesized with hydrothermal method. Single-crystal X-ray diffraction analysis reveals that complexes 1-3 were isostructural crystallize and both of complexes are binuclear molecules. In the complexes 1-3, the coordination number is nine. Each metal is bound to two 3, 4-tdc ligand, one 3,4-Htdc ligand, one phen and two water molecule. Complexes 1 and 3 display the red and green light under UV lamp, corresponding the characteristic peaks from 619 nm (5D0→7F2) and 545 nm (5D4→7F5). Complex 2 expresses a broad band at 425 nm is attributed to π*→π transition. Furthermore, under the excitation wavelength of 329 nm, the effects of different solvents on complex 1 was discussed and complex 1 could be a potential luminescent probe for detecting nitrobenzene through fluorescence quenching mechanism.