An efficient and scalable strategy to prepare libraries of discrete conjugated oligomers (Đ = 1.0) using the combination of controlled polymerization and automated flash chromatography is reported. From this two-step process, a series of discrete conjugated materials from dimers to tetradecamers could be isolated in high yield with excellent structural control. Facile and scalable access to monodisperse libraries of different conjugated oligomers opens pathways to designer mixtures with precise composition and monomer sequence, allowing exquisite control over their physical, optical, and electronic properties.

A nonstoichiometric Stille coupling polycondensation was first succeeded between 2,5-bis-(trimethylstannyl)thiophene (1) and 4,9-dibromo-2,7-bis(2decyltetradecyl)benzo[lmn][3,8]-phenanthroline-1,3,6,8-tetraone (2) with ratios ranging from 1:1 to 1:10. The model reaction using 2-(tributylstannyl)thiophene (3) and 4,9dibromo-2,7-bis(2-hexyl)benzo[lmn][3,8]-phenanthroline-1,3,6,8-tetraone (4) at a 1:1 molar ratio in the presence of catalytic Pd 2 (dba) 3 /P(o-tolyl) 3 indicated that the rate constant of the second substitution reaction (k 2 ) is 15 times higher than that of the first one (k 1 ). It was found that the selective intramolecular catalyst transfer was promoted by the naphthalene-diimide (NDI) skeleton. The results also provided a new one-pot symmetrical end-functionalization method to synthesize an NDI-based n-type polymer with NDI groups at both α,ω-chain ends.

The controlled synthesis of head-to-tail regioregular poly(3-hexylthiophene) (P3HT) using a dianion-type zincate complex, t Bu 4 ZnLi 2 , is described. The molecular weights of P3HTs could be increased up to 30 kDa by increasing the feed ratio of the monomer to Ni catalyst while maintaining a low polydispersity (PDI < 1.2) and a high regioregularity (>97%, when M n > 10 kDa). Surprisingly, this new system can be used in as-received THF as well as in THF containing protic impurities, such as isopropanol, methanol, and even 1000 ppm water. In addition, the direct synthesis of poly[3-(6-hydroxyhexyl)thiophene] (P3HHT) could be performed without protection based on the developed system.

Regioregular poly(3-hexylthiophene) (P3HT) has been a commonly used p-type semiconducting material for solution processable organic electronics. To establish a living system of "Negishi-type catalyst-transfer polycondensation (NCTP)" using zincate complex as a synthetic method for welldefined P3HT having predictable molecular weight (MW) and low dispersity ( -D), the ligands of Ni catalyst were optimized. As a result, a ligand of 1,2-bis(dicyclohexylphosphino)ethane produced P3HTs with highly controlled number average MWs (1650-32,800) and very low -D values (1.03-1.17). The polymerization results were strongly influenced by steric hindrance based on the factors of cone angle and bite angle of Ni catalysts, and/or electron-donating ability of phosphine ligands. In addition, we succeeded in the two-stage polymerization of P3HT and the synthesis of P3HT-b-poly(3-octadecylthiophene), the latter of which is the first demonstration by NCTP using zincate complex.