The anionic polymerization of diisopropenylbenzene (DIPB) derivatives was conducted in THF at −78°C with a specially designed initiator system prepared from oligo(α-methylstyryl)lithium and an excess potassium tert-butoxide (KOBu t ) (2.7−5.0 equiv to the Li salt). Among the ortho-, meta-, and para-isomers of DIPB derivatives, it was found that the para-isomer (p-DIPB) successfully underwent the living polymerization in a selective manner through one of the two isopropenyl groups under the above stated conditions. With this living polymerization system, soluble polymers with controllable M n values ranging from 7620 to 31 500 g/mol and near monodisperse distributions (M w /M n ≤ 1.03) were obtained for the first time. The obtained living polymers were stable at −78°C even after 168 h and at −40°C after 6 h, in which the intermolecular addition reaction of the chain-end anion to the pendant isopropenyl group could be completely suppressed. In contrast, the living polymerization of either the ortho-or metaisomer was not successful under the same conditions. The block copolymerization of p-DIPB with either styrene (S), 2-vinylpyridine (2VP), or tert-butyl methacrylate ( t BMA) by the sequential addition of such monomers was conducted. Four new PS-block-P(p-DIPB), P2VP-block-P(p-DIPB), P(p-DIPB)-block-P2VP, and P(p-DIPB)-block-P t BMA containing reactive P(p-DIPB) segments were synthesized. On the basis of the block copolymerization results, it is understood that p-DIPB is comparable to 2VP and located between S and t BMA in monomer reactivity. The reactivity increases as follows: S < 2VP ∼ p-DIPB < t BMA, while the nucleophilicity of the living chain-end anion decreases in the following order: PS − > P2VP − ∼ P(p-DIPB) − > P( t BMA) − . ■ INTRODUCTIONIt is known that the intermolecular addition reaction of the chain-end anion to the pendant CH 2 CH bond significantly occurs during the polymerization of 1,4-divinylbenzene (p-DVB). Such the addition reaction results in the formation of highly cross-linked polymers insoluble in solvents. Therefore, p-DVB is generally used as a cross-linking agent to prepare microand macro-gels, but not considered as a typical monomer. 1−9 In 2011, we successfully found that the oligo(α-methylstyryl)-lithium (αMSLi)-initiated anionic polymerization of p-DVB proceeds in a living manner by adding an excess potassium tertbutoxide (KOBu t ) (10 equiv or more). 10 In this polymerization, one of the two CH 2 CH bonds selectively participated the polymerization to quantitatively give the soluble poly(p-DVB)s with predictable M n values up to 60 500 g/mol and near monodisperse distributions (M w /M n ≤ 1.05). 11 The living nature of this system was also guaranteed by the quantitative formation of poly(p-DVB)-block-poly(2-vinylpyridine) and poly(p-DVB)-block-poly(tert-butyl methacrylate) by the sequential addition of p-DVB and then 2-vinylpyridine or tert-butyl methacrylate to the above initiator system. 12The success of the living anionic polymerization of p-DVB may possibly be attributed by ...