Source of material 1,2,4,5-benzenetetracarboxylic acid( 0.508 g, 2m mol; 1,2,4,5-BTC) and NaOH (0.16 g, 4mmol) were dissolved in 15 ml water. Asolution of Cu(NO 3)2 ·3H2O(0.242 g, 1mmol) in 10 ml methanol was added, and the resulting mixture was stirred at 333Kfor 4h ,t hen cooled to room temperature.S ome weeksl ater, blue block-shapedcrystals were grownfrom the filtrate by slow evaporation. The crystal structure consists of the heteronuclear copper and sodium complex containing 1,2,4,5-benzenetetracarboxylic acid being partly deprotonated and m2-bridging. All Cu II and Na I atoms are situated on special positions and are six-coordinated in distorted octahedral environments. The Na I is coordinated by two carboxyl Oatoms from two 1,2,4,5-BTC ligands (d(Na-O4) = 2.276(1) Å)and four Oatoms of four bridging water molecules (d(Na-O)=2.458(2) Å,2.459(2) Å,2.494(2) Å and 2.596(2) Å). The Cu II is coordinated by six watermolecules in which four are bridging( d (Cu-O7) =2 .030(2) Å, d(Cu-O6) =2 .301(2) Å) two are non-bridging (d(Cu-O8) =1 .973(2) Å). The bridging water molecules regularly link one Cu II and two Na I atoms so that ao ne-dimensional linear chain structure is generated. The distancesofadjacent Cu···Naand Na···Na pairs are 3.652(2) Å and 3.888(3) Å,respectively. The intra-and intermolecular hydrogen bonds consolidate the chain structure and join it into three-dimensional network. The hydrogen bond O···O lengths are in the range of 2.392(2) Å to 2.865(2) Å.