A series of fluorene and bipyridine (bpy) copolymers were synthesized, and their optical properties were investigated in the presence of zinc(II). By adjusting the bpy content in the polymer backbone, the emitting color of the polymer solution could be tuned from initial blue to green to white and violet when it interacted with zinc(II) ions. The counteranions of zinc(II) ions were also found to influence the optical properties of copolymers greatly.