Vinyl monomers containing a bis-crowned Malachite Green leuconitrile moiety were copolymerized with several vinyl monomers to afford polymers carrying the photochromic crown ether moiety at the side chain. The polymeric crowned Malachite Green derivatives were found to have the higher metal ion complexing ability toward K+ and Cs+ than Li+ and Na+, the ion selectivity being quite different from their corresponding monomeric analogues. The photochromism of their Malachite Green moiety was affected considerably by the metal ion complexation of their crown ether moiety. The decoloration reaction of the photoinduced cationic form was also governed by the polymer rheology in solution.