The captodative (cd) effect in radical polymerization and polymer properties is reviewed. A cd substitution with olefins and methanes would promote a radical polymerization, in spite of resonance stabilization of the resulting radicals and sterically hindered 1, 1-disubstituted molecules. The principal advantage of cd olefins is the observation of solvent effects in the polymerization in spite of a radical mechanism, the highly spontaneous polymerization, and the consequent utility of the spectroscopic methods to elucidate the reaction features and the mechanism of the polymerization. In particular, the complexed radical and penultimate effect are demonstrated spectroscopically. In addition, cd substituted ethanes provide unique initiators, which induce a molecular weight that increases during a polymerization, and permit block copolymerization through a radical mechanism. Because of their high polarity, high density, unsymmetric, and bifunctional substitutions, polymers obtained from cd substituted monomers can exhibit desirable optical, thermal, mechanical, and solubility properties. (C) 2003 Elsevier Science Ltd. All fights reserved.