In this chapter, assembled structures of the cyclic pentamers, pillar[5]arenes, and cyclic hexamers, pillar[6]arenes, in the crystal state are discussed. Pillar[5]-and pillar[6]arenes have clear cylindrical pillar-shaped structures when compared with other macrocyclic compounds. Therefore, the assembled structures of pillar[n]arenes in the crystal state are easily analyzed, and this pre-organized conformation of pillar[n]arenes mainly forms three crystal structures: herringbone, one-dimensional channels and slipped-stacked. The assembled structures of pillar[n]arenes largely depend on the ring size, substituents, guests and solvents used to obtain single crystals. In particular, the ring size of the pillar[n]arene greatly influences their assembled structures. Pillar[6]arenes are highly symmetrical hexagonal structures, therefore the assembled structures of pillar[6]arenes showed highly ordered one-dimensional structures. We also describe bulk state materials, such as liquid and liquid crystal pillar[n]arenes, and the crystal state-assembled structures of larger pillar[n]arene homologs (n=8, 9, 10).