Merging polyacenes and cationic helicenes: from weak to intense chiroptical properties in the far red region†
A series of helical tetracenes and pentacenes was synthesized from cationic  and helicene precursors. These colorful acenes fluoresce in the far red region. While helicene-based pentacenes exhibit chiroptical properties mainly in the UV region, helicene-derived tetracenes show enhanced ECD in the visible range, in addition to clear CPL responses. This difference is rationalized using first principles.