Development of lanthanide based complexes crossed an overriding interest lately, considering their photophysical and magnetic significance. Pyridine‐diacylhydrazones were important multidentate ligands employed for the synthesis of complexes with d-block metal ions, but less with f-block ions. Herein a mononuclear complex [Er(H2L)(H2O)4](NO3)3 (1) is reported which is obtained from the reaction of Dy(III) nitrate and a pentadentate organic ligand 2,6-diacetylpyridinebis-(semicarbazone). Complex 1 was characterized by elemental analysis, IR spectroscopy and single crystal X-ray crystallography. A strong band in the spectrum of the ligand at 1698 cm-1 attributed to ν(C=O) is shifted to 1664 cm-1 and the band from 1567 cm-1 attributed to azomethine group ν(C = N) of the ligand also drives to lower energy in the complex (1545 cm-1), indicating coordination of the nitrogen atom of the azometine bond and carbonylic oxygen atoms of semicarbazone arms of the ligand. The spectrum also contains v(N-H) absorptions, suggesting that the proton of the ligand'shydrazine group remains unchanged after complexation. The bands from approx. 3256 and 824 cm-1, most likely belong to the coordinated water molecules. The wide band at 1380 cm-1 was attributed to uncoordinated nitrate ions. Single-crystal X-ray analysis revealed that compound 1 crystallizes in the orthorombic space group P21/n, a = 9.9722(5),b = 22.7430(12), c = 10.0541(10) Å, β = 96.359(6), V = 2266.22 (2) Å3. The asymmetric unit of [Er(H2L)(H2O)4](NO3)2(Figure) consists of complex cation [Er(H2L)]3+that is neutralized by three nitrate anions in the external sphere The neutral ligand H2L coordinates through both nitrogen atoms of azomethinic groups and two carbonylic oxygen atoms. Photoluminescence properties of [Er(H2L)(H2O)4](NO3)3 (1) are under investigation.