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Four new lanthanide(Ш) coordination polymers, [Ln( p-aminobenzoate)(DMF)(HCOO) (HO)] (Ln = Sm 1, Tb 2, Pr 3) and {[Pr(2,5-dcp)(CHCOO)(HO)]·1.5HO} ( 4) (DMF = N, N-dimethylformamide, 2,5-dcp = pyridine-2,5-dicarboxylate), have been synthesized by hydrothermal method. The structures are determined by the single-crystal X-ray diffraction. The four polymers all crystallize in the monoclinic space group P2/n. Polymers 1 and 2 are isostructural; both Sm ion of polymer 1 and Tb ion of polymer 2 are eight-coordinate. Although polymer 3 possesses the same asymmetric unit as polymers 1 and 2, the three are not isomorphous. The Pr ions in polymers 3 and 4 are nine-coordinate. In polymers 1, 2 and 3 the neighboring units are bridged by formyloxy and extend into infinite chains, which are connected by hydrogen bonds to form a hydrogen bond network. However, polymer 4 is bridged by pyridine-2,5-dicarboxylate and acetates to form an infinite 3D network. At room temperature, the IR, UV-Vis-NIR and emission spectra of the four polymers were measured and analyzed. The four polymers emit in the visible or NIR region. The luminescent properties are discussed. [ABSTRACT FROM AUTHOR]