How to build a molecular Helmholtz coil? The possibility to create a Helmholtz coil at the molecular level is studied via the induced magnetic responses of several small cyclic hydrocarbon dimers with formula (CnHn)2 and Dnh symmetry (n = 6–10). Our results reveal that for n ≥ 8, π-electrons give rise to a uniform magnetic field within the central region between rings, satisfying the Helmholtz coil condition. This uniformity is independent of the intensity of the induced magnetic field.