New vectors for intracellular delivery: The conformational preferences of non‐cationic and amphipathic [l‐Aia‐Xxx]n oligomers were investigated by CD and NMR. All of the proposed FITC‐6‐Ahx‐[l‐Aia‐Xxx]4‐NH2 oligomers were internalized by cells highly efficiently, clearly showing the importance of the azepinone‐constrained l‐Trp analogue (l‐Aia) for cell penetration. The compounds were also explored in an in vitro BBB permeation assay.