The title compound crystallizes in both a yellow and a green phase. The pyridinium cations form bifurcated hydrogen bonds to the CuCl42- anions to form molecular species. The packing of these molecular species force the CuCl42- chromophore to be distorted more toward a square planar geometry in the green phase. The packing in both phases appears to be strongly influenced by C-H...CI electrostatic interactions. [GRAPHICS]