In both title compounds, C(10)H(13)BO(3)S, (I), and C(13)H(17)BO(3), (II), the molecules adopt nearly planar conformations. The crystal packing of (I) consists of a supramolecular two-dimensional network with a herringbone-like topology formed by self assembly of centrosymmetric pairs of molecules linked via dipole-dipole interactions. The crystal structure of (II) consists of a supramolecular two-dimensional network built up from centrosymmetric pairs of molecules via π-π interactions. These pairs of molecules are self-organized in an offset fashion related by a symmetry centre, generating supramolecular ribbons running along the [101] direction. Neighbouring ribbons are stacked via complementary van der Waals and hydrophobic methyl-methyl interactions.