Graphical Abstract: A lanthanum(III) cyanoacetate complex {[La2(CNCH2COO)6 (H2O)4]∙H2O}n (1) was synthesized and characterized by X-ray single-crystal analysis. The complex 1 exhibits one-dimensional coordination polymer structure. Cyanoacetate ligands coordinated in the bidentate bridging and tridentate-chelating bridging modes. The cyano-group of ligand is not coordinated to the lanthanide ion.