The classical helicenes contain angularly fused aromatic rings (Figure ) and express strong chiroptical responses due to their intrinsic helical chirality. A logical approach to enhance the chiroptical properties is an elongation of the helical structure. However, synthesis of long helicenes is very challenging as it requires the introduction of large strain and regioselective fusion of many rings. So far, the longest helicene is a [16]helicene reported by Fujita et al. Alternatively, multiply fused helicenes have been reported and many of them show improved chiroptical properties as compared to their single helicene counterparts. Another way is to increase the size of a helicene by alternation of the linear and angular ring fusion, the so-called "expanded helicenes" approach (Figure ). Such expansion could enhance the chiroptical properties due to more extended π-conjugation and modulation of the frontier molecular orbital symmetry and transition moments. Synthesis of expanded helicenes is also challenging and several expanded helicenes have been reported in recent years by different synthetic methods (Figure ). For example, Tilley et al reported a tribenzo-, expanded [13]helicene (A) through a three-fold, partially intermolecular [2+2+2] cycloaddition with substrates containing three diyne units. Matsuda et al synthesized a π-expanded helicene that is the helically twisted analogue of kekulene (B) by using a 6-fold ring-closing olefin metathesis reaction as a key step. Toyota et al developed a series of expanded helicenes consisting of up to five fused anthracene units (C) by PtCl2-catalyzed cycloisomerization. However, the enantiomers of the abovementioned expanded helicenes could not be isolated by chiral HPLC at room temperature due to their relatively low racemization barriers. Later, Yashima et al reported the facile synthesis of several consecutively fused expanded helicenes (D) through the trifluoroacetic acid-promoted intramolecular multistep cascade alkyne benzannulations. Notably, the triple-expanded helicene (n=3) showed persistent chirality with the absorption and luminescence dissymmetry factors of up to 1.5 × 10 -2 (|gabs|) and 0.94 × 10 -2 (|glum|), respectively. These studies imply promising chiroptical properties of expanded helicenes but the synthesis of even longer expanded helicenes remains very challenging. Recently, our groups demonstrated that Bi(OTf)3-mediated cyclization of vinyl ethers was a very efficient benzannulation approach for the synthesis of cycloarenes, 9 expanded kekulenes, and twisted carbon nanobelts. We expect that such a reaction could be also used for the synthesis of expanded helicenes if appropriate precursors are designed. In this work, we report the facile synthesis of a series of expanded helicenes Hn (n=1-4) containing 11, 19, 27 and 35 cata-fused benzene rings (Figure ) through a synthetic strategy mainly involving Suzuki coupling followed by Bi(OTf)3-mediated cyclization reaction. The enantiomers of the three longer expanded helicenes (H2-H4) were successfully isolated by chiral HPLC and they all showed high absorption dissymmetric factors.