Guest functionalization of substrates: The appropriate substrates were immersed in a solution of the guest in MeOH (0.05 -0.1 mM) for 1 h, after which they were soaked in pure MeOH twice (5 minutes each). The substrates were then dried under a stream of N 2 . HGC formation was easily observed by eye on mesoporous substrates due to coloration of the films. DFT calculations: Optimized structures, energies and electronic properties were obtained by DFT simulations using the Gaussian and plane waves method as implemented in the CP2K program package . The HGCs on gold were simulated using an Au(111) slab model with four 9x9 layers and periodic boundary conditions were applied. The adsorption energies of the host-guest complexes in the gas phase were computed by comparing the energy of the optimized complex and the energies of the individually optimized CD and catalyst