Reactions in acetonitrile between 1,4-benzene-dicarboxylic acid (C8H6O4) and a hexanuclear complex of lanthanide [Ln(6)O(OH)(8)(NO3)(6)center dot 2NO(3)] with Ln = Y or Tb lead to 1D-coordination polymers with the general chemical formula {[Ln(6)O(OH)(8)](NO3)(2)(bdc) (Hbdc)(2)center dot 2NO(3)center dot H(2)bdc}(infinity), where H(2)bdc stands for 1,4-benzene-dicarboxylic acid (or terephthalic acid). These two compounds are isostructural. The crystal structure has been solved on the basis of the X-ray powder diffraction diagram of the Y-containing compound. This compound crystallizes in the triclinic system, space group P (1) over bar (no. 2) with a = 10.4956(6) angstrom, b = 11.529(2) angstrom, c = 12.357(2) angstrom, alpha = 86.869(9)degrees, beta = 114.272(6)degrees, gamma = 71.624(7)degrees, V = 1264.02 angstrom(3), and Z = 2. The crystal structure can be described as the juxtaposition of linear chains of hexanuclear entities linked to each other by terephthalate ligands. Two additional partially protonated terephthalate ligands spreading laterally to the chain are bound to each hexanuclear entity. Another diprotonated terephthalic ligand and two nitrate ions ensuring the electroneutrality of the crystal structure lie in the interchain space. These two compounds are thermally stable until 200 degrees C. Thanks to a so-called antenna effect, the Tb-containing compound, despite short intermetallic distances, exhibits a strong luminescence under UV irradiation.