Over the last decade, pillararenes have shown remarkable potential in a variety of fields by virtue of their symmetrical pillar-shaped structures, flexible functionalization, and unique host–guest interactions. For diverse pillararene-based functional materials and technical applications, the tailored design and construction of pillararene-based supramolecular structures and assemblies are critical. Rationally modifying pillararenes and guests endows these supramolecular functional materials with stimuli-responsiveness, selective target recognition, and tunable self-assembly, among others. In this review, we summarize various forms of pillararene-based supramolecular assemblies or composite materials, along with their applications. In addition, we specifically introduce the employment of different pillararene-based systems in sensing and detection, adsorption and separation, modification of nanomaterials, and nanomedicines.