Two hexaphenylhexaazatriphenylene L(1) and three quaterpyridine L(2) ligands are well-known to associate around six copper(I) ions to form a cylindrical inorganic cage 1. Spectrophotometric and electrospray mass spectrometry (ESMS) titrations have been conducted to gain information on the thermodynamics and the formation pathway of the assembly 1. From these data, the nature of intermediates present in solution was determined and the association constants of these species were calculated. It was also found that this assembling process occurs with positive cooperativity.