A two dimensional coordination polymer with pseudo-Kagomé net [Cu3(btc)2(NH3)8(H2O)] was prepared from Cu(NO3)2·3H2O and 1, 3, 5-benzenetricarboxylic acid (btc) in ammonia aqua solution and was structurally characterized by X-ray diffraction. The magnetic susceptibility measurements, measured from 2 to 300 K, revealed a weak anti-ferromagnetic inte...