In the even-n [n]cumulenes, the ground-state geometry has perpendicular end-groups as also seen in allene, and the frontier molecular orbitals are helical. Albeit lower than in the odd-n cumulenes, the total current is still fairly high in [4]cumulene and strong unidirectional ring currents appear around the linear carbon wire (Figure ). The resulting magnetic field is enhanced at the carbon atoms where the ring current appears, and points along the carbon chain. The magnetic field approaches the teslarange at this specific point in space.