Click To Stack: Shape-Assisted Self-Assembly of Unflattened Macrocycles into Waveguiding Elastic Crystals

Designing molecular crystals for practical applications requires precise control over intermolecular interactions. We report a click-to-stack strategy to enable facile construction and systematic structural modification of tetraarene-fused cyclooctatetraenes. These saddle-shaped molecules self-assemble into one-dimensional columns with exceptional precision, driven solely by weak van der Waals interactions. Single-crystal X-ray crystallographic and computational studies revealed fully eclipsed π-π stacking, reinforced by the shape complementarity of the negatively curved molecular contour. With alkoxy groups tethered, the antiparallel alignment of coaxial cable-like assemblies produces centimeter-long voidless crystals that exhibit remarkable structural durability under mechanical stress. These glow stick-like elastic crystalline rods display optical waveguiding properties, demonstrating the practical utility of highly anisotropic molecular assemblies with structural uniformity and resilience.