Pyromellitic diimides and naphthalene diimides: From versatile supramolecular building blocks to advanced materials

Cyclic aromatic imides (CAIs), especially the pyromellitic diimides (PMDIs) and naphthalene diimides (NDIs), have pioneered new approaches as important building blocks in supramolecular chemistry. The π-conjugated electron-deficient nature with high heat resistance, chemical stability, two-electron redox activity, high fluorescence quantum yield and self-assembling tendencies has made them significant in wide-ranging applications from supramolecular to materials chemistry and biological sciences. This comprehensive review describes the developments of PMDIs and NDIs supramolecular building blocks (SBBs) in the field of host-guest complexes, including macrocycles, cyclophanes, rotaxanes, catenanes, foldamers, and intercalated complexes. The organization of PMDI and NDI units into supramolecular architectures through hydrogen bonding, π-π stacking, and charge-transfer (CT) interactions is discussed. The formation of supramolecular self-assemblies through other weak interactions leading to nano- and mesoscopic structures is also addressed. The versatile applications of such supramolecular complexes in the areas of electronic and optical materials, gels and dyes, ions/molecule sensors, semiconductors, gas storage/separation, fuel cells and medical probes are explored. Furthermore, their prominent roles in mechano-luminescence, solar cell technologies, and photovoltaic devices are also elucidated. Overall, starting from general molecular characteristics and role of supramolecular interactions in the formation of unique assemblies, the significant contributions of PMDIs and NDIs in interdisciplinary research fields are enlightened. The significance of supramolecular interactions in the construction of self-assembled architectures of macrocyclic and mechanically interlocked molecules related to PMDI and NDI derivatives along with their materials and biological applications is explicated. • Enlightened the importance of PMDIs and NDIs as an emerging class of SBBs. • Surveyed the role of weak interactions in the construction of supramolecular assemblies of macrocycles and mechanically interlocked complexes of PMDIs and NDIs. • Reviewed some prominent applications of supramolecular and polymeric complexes of PMDIs and NDIs. • Summarized a brief understanding on structure-property relationships and significant contributions of PMDIs and NDIs in supramolecular and materials chemistry.