The structure of the 1:2 co-crystalline adduct C8H16N4·2C6H5BrO, (I), from the solid-state reaction of 1,3,6,8-tetra-aza-tri-cyclo-[4.4.1.1(3,8)]dodecane (TATD) and 4-bromo-phenol, has been determined. The asymmetric unit of the title co-crystalline adduct comprises a half mol-ecule of aminal cage polyamine plus a 4-bromo-phenol mol-ecule. A twofold rotation axis generates the other half of the adduct. The primary inter-species association in the title compound is through two inter-molecular O-H⋯N hydrogen bonds. In the crystal, the adducts are linked by weak non-conventional C-H⋯O and C-H⋯Br hydrogen bonds, giving a two-dimensional supra-molecular structure parallel to the bc plane.