Tetramethylated resorcin[4]arene (MRCT) forms 'head-to-head' arranged self-dimers incorporating neutral guest molecules methanol, ethanol, and imidazole within the cavity, with the MRCT:guest composition of 2:2, while unsubstituted resorcin[4]arene forms 1:1 monomers, showing the significance of the methyl substituents of the MRCT rings in the capsule formation through methyl(...)methyl hydrophobic interactions between the facing substructures, as evidenced by X-ray diffraction.