On-surface synthesis of non-benzenoid conjugated polymers by selective atomic rearrangement of ethynylarenes Jiménez Martín, Alejandro Villalobos Romero, Federico Cuerva Carvajal, Juan Manuel González Campaña, Araceli Here, we report a new on-surface synthetic strategy to precisely introduce five-membered units into conjugated polymers from specifically designed precursor molecules that give rise to low-bandgap fulvalene-bridged bisanthene polymers. The selective formation of non-benzenoid units is finely controlled by the annealing parameters, which govern the initiation of atomic rearrangements that efficiently transform previously formed diethynyl bridges into fulvalene moieties. The atomically precise structures and electronic properties have been unmistakably characterized by STM, nc-AFM, and STS and the results are supported by DFT theoretical calculations. Interestingly, the fulvalene-bridged bisanthene polymers exhibit experimental narrow frontier electronic gaps of 1.2 eV on Au(111) with fully conjugated units. This on-surface synthetic strategy can potentially be extended to other conjugated polymers to tune their optoelectronic properties by integrating five-membered rings at precise sites. 2023-01-27T08:43:31Z 2023-01-27T08:43:31Z 2022-12-20 journal article Chem. Sci., 2023, Advance Article. DOI: [10.1039/d2sc04722e] https://hdl.handle.net/10481/79405 10.1039/d2sc04722e eng info:eu-repo/grantAgreement/EC/H2020/677023 http://creativecommons.org/licenses/by/4.0/ open access Atribución 4.0 Internacional Royal Society of Chemistry