The prepn. of a 3. component crystal of 2,2'-dihydroxybiphenyl (1), phenazine (2) and acridine (3) is described whose possible existence was produced from the structure of a 2:3 cocrystal of 2,2'-dihydroxybiphenyl (1) and phenazine (2). X-ray structures of both crystals are reported. Inspection of the crystal lattice of the 2:3 cocrystal shows that one phenazine mol. forms one and the other 2 H bonds to hydroxy groups of the diol. The mol. forming only one H bond can be replaced successfully by acridine, a 1-H bond acceptor.