4,4′-Isopropylidenediphenol-1,4-diazabicyclo[2.2.2]octane (1/1), (1), C15H16O2.C6H12N2, monoclinic, P2/a, a = 11.385 (2), b = 6.5565 (12), c = 13.076 (2) Å, \beta = 96.240 (11)°, with Z = 2; the two components of the adduct, which each lie across twofold axes, are joined into simple chains via O—H...N hydrogen bonds in a motif with graph set C_{2}^2(17). 4,4′-Oxodiphenol-1,4-diazabicyclo[2.2.2]octane (1/1), (2), C12H10O3.C6H12N2, orthorhombic, P212121, a = 9.4222 (11), b = 11.1886 (15), c = 15.694 (2), with Z = 4; the diamine component is disordered by rotation about the N...N vector, having two orientations [populations 0.76 (1) and 0.24 (1)] rotated by 48 (3)° from coincidence: the components are joined into chains via O—H...N hydrogen bonds in a motif with graph set C_{2}^2(17); pairs of these chains are joined into ladders by C—H...O hydrogen bonds in a motif of graph set R_{2}^2(22). 4,4′-Thiodiphenol-l,4-diazabicyclo[2.2.2]octane (1/1), (3), C12H10O2S.C6H12N2, isomorphous, a = 9.5785 (11), b = 11.4525 (13), c = 15.759 (2) Å (and ipso
facto isostructural), with (2); the diamine disorder is characterized by two equally populated orientations related by a rotation about the N...N vector of 37.1 (2)° and pairs of chains are now joined into ladders by C—H...S hydrogen bonds. 4,4′-Thiodiphenol-1,4-diazabicyclo[2.2.2]octane (2/1), (5), (C12H10O2S)2.C6H12N2, monoclinic, P21/n, a = 8.3198 (9), b = 11.4006 (13), c = 15.056 (2) Å, \beta = 104.955 (8)°, with Z = 2; the diamine component of the adduct is disordered across a centre of inversion, and the bisphenol components are linked into chains by O—H...O hydrogen bonds in a motif with graph set C(12). These chains form cross-links via the diamine component by means of O—H...N hydrogen bonds in a C_{3}^3(19) motif to yield sheets within which are large hydrogen-bonded rings described by the unusual graph set R_{8}^8(62).