The new coordination polymer, [K(DNP)(H2O)0.5]n (DNP=2,4-dinitrophenol) was prepared by the reaction of 2,4-dinitrophenol with potassium hydroxide. The molecular structure was determined by X-ray single-crystal dif-fraction analysis, FT-IR techniques, and elemental analysis. The crystal is monoclinic, space group C(2)/c with the empirical formula of C6H4N2O5.5K, Mr=231.21. The unit cell parameters are as follows: a=2.0789(3) nm, b=1.2311(2) nm, c=0.7203(1) nm, b=109.611(15)? V=1.7366(4) nm3, Z=4, Dc=1.769 g/cm3, F(000)=936, (Mo K)=0.617 mm-1. The potassium ions coordinate with all the oxygen atoms of phenolic hydroxyl group and nitro-group of different 2,4-dinitrophenol (DNP) ligands with high coordination number, and form a good cross-linked three-dimensional net structure of which makes the complex with good stabilities. The thermal de-composition of [K(DNP)(H2O)0.5]n has only an intense exothermic process in the temperature range of 338—343 ℃ corresponding to a mass loss of 75.02%. The final decomposition residue is potassium isocyanide. The new coordination polymer, [K (DNP) (H2O) 0.5] n (DNP = 2,4-dinitrophenol) was prepared by the reaction of 2,4-dinitrophenol with potassium hydroxide The crystal is monoclinic, space group C (2) / c with the empirical formula of C6H4N2O5.5K, Mr = 231.21. The unit cell parameters are as follows: a = 2.0789 (3) nm, b = 1.2311 (2) nm, c = 0.7203 nm, b = 109.611 nm, Z = 4 and Dc = 1.769 g / cm3, The potassium ions coordinate with all the oxygen atoms of phenolic hydroxyl group and nitro-group of different 2,4-dinitrophenol (DNP) ligands with high coordination number, F (000) = 936, (Mo K) = 0.617 mm- and form a good cross-linked three-dimensional net structure of which makes the complex with good stabilities. The thermal de-composition of [K (DNP) (H2O) 0.5] has only an intense exothermic process in the temperature range of 338 -343 ° C corresponding to a mass loss of 75. 02%. The final decomposition residue is potassium isocyanide.