Two supramolecular complexes were prepared using cucurbiturils [CBs] as hosts and a four-armed p-xylene derivative (M1) as a guest molecule. The single crystals of these two complexes were obtained and successfully analyzed by single-crystal X-ray diffraction (SCXRD). An unexpected and intriguing 1:2 self-assembly arrangement between the M1 and CB[8] was notably uncovered, marking its first-time observation. These host-guest complexes exhibit distinctive photophysical properties, especially emission behaviors. The invaluable insights derived from these precious single-crystal structures provide both precise structural information regarding the supramolecular complexes and a deeper understanding of the intricate mechanisms governing their photophysical properties.