Phenanthrene[2]arene 1 with excellent adsorption capacity for benzene was synthesized in high yield. Activated crystals of 1 have been successfully used to separate PhH from equimolar mixture of PhH and Cy and the purity of the PhH can reach 98.4%.

A novel pyromellitic diimide-extended pillar[6]­arene was synthesized in two steps with moderate yield for the first time. It showed a symmetrical stretched hexagon structure and could form 1:2 complexes with polycyclic aromatic hydrocarbons in solution. Interestingly, a linear supramolecular array between complex 1@G4 2 and pyrene through π···π stacking interactions was also observed in the solid state.

The complexation between the pyromellitic diimide-extended pillar[6]aren host and carboxylate guests in solution was investigated in detail. It was found that the host could form 1∶2 complexes with carboxylate salts in solution. Interestingly, the complexation and decomplexation of the complexes between the host and the guest could be achieved by changing the pH of the solution, and the process could also be observed by naked eye.