The host-guest interactions between cucurbit [7] uril and a series of novel cationic bis (4, 5- dihydro-1 H-imidazol-2-yl) arene and 1-(4, 5-dihydro-1 H-imidazol-2-yl)-and 1, 3-bis (4, 5- dihydro-1 H-imidazol-2-yl)-adamantane guests have been investigated in aqueous solution using UV-vis and NMR spectroscopy, and electrospray mass spectrometry. With the exception of the 1, 3-bis (4, 5-dihydro-1 H-imidazol-2-yl) adamantane (which binds ...