The novel bidentate ligand 1, 4-di(1 2,3-triazol-1-yl) butane (bbtr) reacts with Fe(CIO4)(2)(.)6H(2)O to form the 2D coordination polymer with (3,6) network topology. The {[Fe(bbtr)(3)](CIO4)(2)}(infinity) represents an example of spin-crossover material based on 1,2,3-triazole as donor group, and displays an abrupt spin transition accompanied by a thermal hysteresis loop (T-1/2(down arrow) = 101 K and T-1/2(up arrow) = 109 K).