A combination of variable-temperature H-1 NMR spectroscopy and molecular mechanics calculations have been used to probe the factors that determine the rate of macrocyclic ring rotation in benzylic amide [2]catenanes. The results show that the interlocked macrocycle dynamics are governed by a delicate combination of steric effects, intricate inter-macrocyclic arrays of hydrogen bonds, pi-pi stacking, and T herringbone-type interactions. A cascade of hydrogen-bond ruptures and formations is the principal event during circumvolution (complete rotation of one macrocyclic ring about the other) but is accompanied by a series of cooperative conformational and co-conformational rearrangements that help to stabilize the energy of the molecule. The experimental picture is consistent both when activation energies are measured from the coalescence of NMR signals and when rate constants are directly measured by spin polarization transfer by selective inversion recovery (SPT-SIR) methods. The nature of the circumrotational process means that the precise structure of the diacylaromatic units has a tremendous effect on the frequency of macrocyclic ring rotation : a 2,5-thiophene-based catenane rotates 3.2 million-fold faster than the analogous 2,6-pyridine-based system at room temperature! The polarity of the environment also plays a crucial role in determining the inter-ring dynamics : reducing the strength of the ground-state hydrogen-bonding network by employing hydrogen bond-disrupting solvents (methanol, DMSO) increases the rate of rotation by lowering the activation energy for circumvolution (normally in the region of 11-20 kcal mol(-1)) by up to 3.2 kcal mol(-1). This allows exquisite control over the kinetics of the translational behavior of the individual components of an interlocked molecular system, a key requirement for their development as nanoscale shuttles, switches, and information storage systems.