2,6-Dinitrophenol (2,6-DNP) complexes with lanthanide series including yttrium (except Pm, Tm, and Lu) have been synthesized and their crystal structures have been analyzed by X-ray diffraction methods. Singlecrystal X-ray structure determinations have been performed at 296 K on the Ce$ ightarrow$Yb species and shown them to be isomorphous, triclinic, P1, a = 8.6558(2)$ ightarrow$8.5605(3) $AA$, b = 11.8813(3)$ ightarrow$11.6611(4) $AA$, c = 13.9650(3) $ ightarrow$13.8341(5) $AA$, $alpha$ = 73.785(1)$ ightarrow$73.531(2)o, $eta$ = 74.730(1)→74.903(2)${^{circ}}$, $gamma$ = 69.124(1)→ 69.670 $(2){^{circ}}$, V = 1266.86(5)→1221.53(7) $$AA^{3}$$</TEX>, Z = 2. In Ln(III) complexes, three 2,6-DNP ligands coordinate directly to the metal ion in the bidentate fashion. The nine coordinated Ln(III) ion forms slightly distorted tri-capped trigonal prism. There are no water molecules in the crystal lattice. The dependences of metal to ligand bond lengths are discussed on the atomic number of lanthanide elements. The thermal properties of lanthanide complexes of 2,6- DNP have also studied by TG-DTG and DSC thermal analysis methods.