The first stable π-dimer of a tetrathiafulvalene (TTF) cation radical encapsulated in the cavity of cucurbit[8]uril has been isolated at room temperature and fully characterized; it shows absorption bands at 400, 540 and 760 nm, characteristic of the TTF cation radical dimer.

cis-Diaminostilbene dihydrochloride encapsulated in cucurbit[7]uril does not spontaneously isomerize to the trans isomer at room temperature as a result of the strong host–guest interactions including strong hydrogen bonds between the two protonated amine termini of the C-shaped guest and the portal oxygen atoms of the host.

A novel three-way supramolecular switch based on the interconversion of hetero-guest-pair (D–A) and homo-guest-pair (D₂ or A₂) inclusion inside cucurbit[8]uril is reported, which can be selectively controlled by chemical or electrochemical stimuli.