The title two-component mol-ecular crystal [systematic name: 3-(dihy-droxy-boran-yl)benzoic acid-1,3-dimethyl-7H-purine-2,6-dione (1/1)], C(7)H(7)BO(4)·C(7)H(8)N(4)O(2), comprises theophylline and 3-carb-oxy-phenyl-boronic acid mol-ecules in a 1:1 molar ratio. In the crystal, mol-ecules are self-assembled by O-H⋯O and N-H⋯N hydrogen bonds, generating layers parallel to (-209). The layers are stacked through π-π [centroid-centroid distance = 3.546 (2) Å] and C-H⋯π inter-actions.