Coordination (co)polymerization of polar vinyl monomers is a theoretical challenge of polymer science, of which monomers bearing a polar group close to the reaction double bond are rather difficult. Herein, we report the first coordination-insertion polymerization of the cheap and commercially available ortho-fluorostyrene (oFS) by using rare-earth metal-based catalytic systems. Under mild conditions, high activity (2.3 x 10(6) g polymer mol(Sc)(-1) h(-1)) and perfect syndioselectivity (rrrr > 99%) as well as high conversion (99%) are obtained to give poly(oFS)s with high molecular weights and narrow molecular weight distributions. In addition, the copolymerization of oFS and styrene (St) performs fluently, and the insertion of polar oFS can be facilely tuned in a full range of 0-100% simply by changing the oFS-to-St ratio. Competitive reactivity ratios of r(oFS) = 0.295 and r(St) = 0.289 indicate the unprecedented random microstructure of the resultant copolymers.