Morphological Self-assembly of Enantionpure Allenes for Upstanding Chiral Architectures at Interfaces. Chiral surfaces have been intensively investigated in the last years due to their great potential for surface sensing technology. However, the very weak or absent chiroptical properties of the molecules commonly used for the construction of chiral surfaces hampers their exploitation for real devices. In this work, multifunctional chiral allenes are for the first time explored for the construction of surface-confined nanoarchitectures. Gas-phase characterization, low-temperature scanning tunneling microscopy and molecular-dynamics simulations reveal that the dominance of molecule–molecule over molecule–substrate interactions leads to regular diastereomeric domains of up-standing chiral architectures (UCAs) with the optically active units being largely decoupled from the substrate. The outstanding chiroptical responses presented by such allene derivatives along with the opportunity to further functionalization via the terminal alkyne exposed on top of the monolayer-thin architectures make such UCAs promising key ingredients for chirality sensing applications.