A hydro(solvo)thermal reaction between zinc perchlorate and ethyl ester of a new pyridinecarboxylate bridging ligand of similar to17.6 Angstrom in length yields a unique coordination polymer which contains both interdigitated infinite 1D chains and interpenetrated 2D rhombohedral grids [Zn-2.5(L)(4)(mu(3)-OH)].(H2O)(5), 1, where L is 3-{[4-(4-pyridylethenyl)phenyl]ethenyl}benzoate. The 1D chains contain mu(3)-bridged hydroxy groups and have a [Zn-4(mu(3)-OH)(2)(L)(6)] stoichiometry, while the 2D grids have a Zn(L)(2) formula and diagonal distances of 31.7 and 25.2 Angstrom. Crystal data for 1: monoclinic space group P2/c, a = 15.686(2) Angstrom, b = 12.6103(16) Angstrom, c = 38.999(5) Angstrom, beta = 98.397(2)1, and Z = 4.