π−π interactions are among the most important intermolecular interactions in supramolecular systems. Here we determine experimentally a universal parameter for their strength that is simply based on the size of the interacting contact surfaces. Toward this goal we designed a new cyclophane based on terrylene bisimide (TBI) π‐walls connected by para‐xylylene spacer units. With its extended π‐surface this cyclophane proved to be an excellent and universal host for the complexation of π‐conjugated guests, including small and large polycyclic aromatic hydrocarbons (PAHs) as well as dye molecules. The observed binding constants range up to 108 M−1 and show a linear dependence on the 2D area size of the guest molecules. This correlation can be used for the prediction of binding constants and for the design of new host−guest systems based on the herewith derived universal Gibbs interaction energy parameter of 0.31 kJ/Å2 in chloroform.