AbstractThe kinetics of the polymerization of styrene with oligostyryllithium and butyllithium in the presence of electron donors was investigated calorimetrically. There is no simple correlation between the accelerating effect (1,2‐dimethoxyethane>tetrahydrofuran>N,N,N′,N′‐tetramethylethylenediamine = triethylamine) of the individual electron donors upon the polymerization and their ability to form complexes with the respective organolithium compounds. This is qualitatively explained by considering preceding coordination reactions between organolithium compounds (or their complexes with electron donors) and the monomer in the reaction scheme. An irreversible degradation reaction between butyllithium and 1,2‐dimethoxyethane occurring atT>278 K is described. The products of this reaction are lithium methoxide, decane and hexyl met