Two lanthanide(III) complexes, [Ln(atma)(3)(H2O)(2)] have been synthesized (Ln=La (1) and Nd (2); Hatma=[5-amino-1,3,4-thiadiazol-2-yl]thioglycolic acid). The structure of Hatma ligand and complexes 1, 2 have been determined by X-ray structural analysis and the structure parameters were analyzed as follows: Hatma, monoclinic, C2/c, a=2.141 9(9) nm, b=0.400 76(17) nm, c=1.750 0(8) nm, V=1.495 0(11) nm(3), Z=4; 1, triclinic, P (1) over bar, a=0.882 0(3) nm, b=1.230 6(4) nm, c=1.258 6(4) nm, V=1.291 3(7) nm(3), Z=2; 2, triclinic, P (1) over bar, a=0.883 4(4) nm, b=1.228 3(5) nm, c=1.251 0(5) nm, V=1.282 1(9) nm(3), Z=2. These two complexes are isomorphic and have one-dimensional chain and rich hydrogen bonds which result in three-dimensional supramolecular structures. The complexes were determined by IR. TGA, elemental analysis and single crystal X-ray diffraction. The antimicrobial assays indicate that the two complexes show better activities than free ligand Hatma. The promoting