Oligo (para-phenylene) s (DAOPPs) 2a–2d (n ¼ 1–4) with terminal donor–acceptor substitution (D ¼ C6H13O, A ¼ NO2) were prepared by applying Suzuki cross-couplings for chain extension and end capping. The push–pull effect induces short-reaching polarizations of the chain consisting of conjugated but twisted benzene rings, which was studied by NMR measurements. Electron excitation from the ground-state S0 to the more planar first- ...
