Azulene in a Bowl: A Nonalternant Buckybowl With 5/7 Topology, Azulene‐Derived Properties, and Fullerene Complexation

Despite the intriguing potential of azulene‐embedded nanocarbons, their integration into curved buckybowl architectures has remained unexplored due to synthetic and stability challenges. Herein, we report an azulene‐containing buckybowl 6 , synthesized via a concise four‐step route where the azulene core remains stable without rearrangement to naphthalene. Single‐crystal X‐ray analysis revealed that 6 adopts a nonalternant, bowl‐shaped geometric configuration. Unlike classical buckybowls (e.g., corannulene, dibenzo[a,g]corannulene, and summane), 6 exhibits distinct azulene‐derived properties: red‐shifted UV‐vis absorption, anti‐Kasha photoluminescence, and reversible proton‐responsive behavior. Theoretical studies reveal unique aromaticity in its central pentagon, diverging from known pentagon‐containing buckybowls. Furthermore, it was found that buckybowl 6 can assemble with fullerene C 60 or C 70 in a 1:1 stoichiometry. This work establishes 6 as the unique azulene‐based buckybowl and pioneers a design strategy for nonalternant, positively curved π‐systems with 5/7 ring topologies and tunable optoelectronic properties.