Abstract: | The partial fluorination of polycyclic aromatic hydrocarbons often produces a layered crystal packing, where fluorinated aromatic surfaces are stacked over nonfluorinated aromatic surfaces. Herein, we report the synthesis and crystal packing of partially fluorinated [4]helicenes with steric congestion resulting from H and F atoms in the fjord region. F6‐[4]Helicene forms head‐to‐tail columnar stacks consisting of an alternate arrangement of perfluorinated and nonfluorinated naphthalene moieties. With decreasing fluorine content, aromatic stacking switched from arene?fluoroarene (ArH?ArF) hetero‐stacking to ArH?ArH/ArF?ArF homo‐stacking with the help of intermolecular C?H???F contacts in the fjord region. As a result, head‐to‐head columnar stacks appear. Therefore, the conventional ArH?ArF stacking motif is not always applicable to Fn‐[4]helicenes with twisted π‐surfaces. |