The relationship between ideal copolymerizating behavior and the nature of reactive species of anionic copolymerization in nonpolar solvent has been inherently analyzed. The quantitative expression of in O'Driscoll-Kuntz theory has been unambiguously exploited and elucidated. It is postulated that system of anionic copolymerization in nonpolar solvent becomes "ideal" copolymerization system
only if reactive species coexist in dimeric and monomeric. Only in these cases O'Driscoll-Kuntz theory is adaptable.