Orange-red crystals of [Pt(CN)(2)(bpy)] (bpy = 2,2' - bipyridine) and [Pt(CN)(2)(i-biq)] (i-biq = 3,3'-biisoquinoline) show completely different temperature-dependence of emission behavior which has been explained in terms of the characteristic change of each crystal structure based on the platinum-platinum and ligand pi-pi interactions.