The Nd III coordination compounds [Nd(4-pytza) 3 (H 2 O) 2 ]· 2H 2 O (1) and [Nd(4-pytza) 2 (H 2 O) 4 ]Cl·2H 2 O (2) [H4-pytza = 5-(4-pyridyl)tetrazole-2-acetic acid] were synthesized by reactions of K4-pytza and NdCl 3 ·6H 2 O at different pH values. Single crystal X-ray diffraction analysis reveals that 4-pytza ligands in 1 in a μ 1,3 -COO syn-syn or μ 1,1,3 -COO bridging mode coordinate to two central Nd III atoms to