Living polymerizations play a central role in polymer chemistry, however, conjugated materials synthesis is currently dominated by non-controlled, step-growth polycondensation polymerizations. Synthesizing well-defined π-conjugated polymers is very limited in scope. Catalyst transfer polycondensation reactions are one of the most promising methods to prepare π-conjugated polymers in a controlled, chain-growth manner. Through theoretical investigations, mechanistic studies, monomer and catalyst design, our group has largely expanded the scope of this methodology. Lately, we produced the first example of isolated living π-conjugated polymer chains. This approach has considerable potential to recycle various catalysts and reduce environmental impact. Moreover, we also developed the synthesis of monodisperse sequence-defined π-conjugated oligomers. This method enables the absolute control over both the chain-length and monomer sequence at single-monomer precision, which provides comprehensive understanding of the polymer structures and properties. These advances expand the scope of well-defined π-conjugated polymers and enable more complex structures, such as statistical or block copolymers afforded through chain extension or the combination of functional external initiators and end-capping agents. The introduction of branching points, grafts, and loops in the design of complex architectures offers an opportunity to tailor the physical and electronic properties of conjugated polymers through self-assembly, without changing their composition. To date, our group has synthesized and investigated an array of complex architectures, including stars, macrocycles, and bottlebrush polymers. Recently, we reported the first synthesis of all-conjugated bottlebrush polymers that form fibrous end-on-end assemblies via thermal annealing, a property that has not been shown for unconjugated polymers.
