A new tetradecaborate, [H3N（CH2）2NH3]2[B14O20（OH）6]（1）, was synthesized by a boric acid ＇flux＇ method, and characterized by X-ray powder diffraction, ICP, IR, TGA and DTA analyses. Single-crystal X-ray diffraction analysis showed that it crystallized in the monoclinic space group P1（No.2） with a=0.85092（10） nm, b=0.88678（11） nm, c=1.00724（13） nm, α=95.099（2）°, β=96.950（2）°, γ=116.845（2）°, V=0.66425（14） nm^3, Z=2, R1=0.0625[1〉2σ（I）], and WRE=0.1172（all data）. The molecule structure of compound 1 comprises the isolated polyanion clusters [B14O20（OH）6]^4- and diprotonated ethylenediamine molecules. Each polyanion cluster contains an 8-ring enclosed by six B3O3 3-ring units. Adjacent clusters are further connected with each other through strong hydrogen-bonding interactions of N（O）-H…O to form a three dimensional（3D） supramolecular structure with 2D pseudo channels along the [010] and [001] directions. The diprotonated ethylenediamine molecules located in the channels interact with the host through extensive hydrogen-bonds. Compound 1 presents few example containing isolated polyborate anions synthesized by a boric acid ＇flux＇ method.
