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This perspective explores the idea of using mechanical bonds in the design and construction of metal-organic framework (MOF) materials.We provide examples of how and why mechanical bonds have been used in MOFs to date and examine different ways the mechanical bond can be incorporated into a MOF linker. Furthermore, we suggest ways that linkers with mechanical bonds could be used for the creation of MOFs with interesting topologies and properties dictated by the interlocked nature and dynamics of the mechanical bond.

Hybrid ultramicroporous materials, HUMs, are comprised of metal cations linked by combinations of inorganic and organic ligands. Their modular nature makes them amenable to crystal engineering studies, which have thus far afforded four HUM platforms (as classified by the inorganic linkers). HUMs are of practical interest because of their benchmark gas separation performance for several industrial gas mixtures. We report herein design and gram‐scale synthesis of the prototypal sulfate‐linked HUM, the fsc topology coordination network ([Zn(tepb)(SO4)]n), SOFOUR‐1‐Zn, tepb=(tetra(4‐pyridyl)benzene). Alignment of the sulfate anions enables strong binding to C2H2 via O⋅⋅⋅HC interactions but weak CO2 binding, affording a new benchmark for the difference between C2H2 and CO2 heats of sorption at low loading (ΔQst=24 kJ mol−1). Dynamic column breakthrough studies afforded fuel‐grade C2H2 from trace (1 : 99) or 1 : 1 C2H2/CO2 mixtures, outperforming its SiF62− analogue, SIFSIX‐22‐Zn.