The high storage capacity versus high selectivity trade-off barrier keeps a daunting challenge for addressing practical acetylene (C 2 H 2 ) adsorbent. A structure-performance relationship screening for sixty-two high-performance metal-organic framework adsorbents reveals that a moderate pore size distribution around 5.0-7.5 Å is critical to fulfill this task. Motivated by this inspiration, a precise pore space partition approach was involved to partition 1D hexagonal channels of typical MIL-88 architecture into finite segments with pore sizes varying from 4.5 Å (SNNU-26) to 6.4 Å (SNNU-27), 7.1 Å (SNNU-28), and 8.1 Å (SNNU-29). Coupled with bare tetrazole N sites (6 or 12 bare N sties within one cage) as high-density H-bonding acceptors for C 2 H 2 , the target MOFs offer a good combination of high C 2 H 2 /CO 2 adsorption selectivity and high C 2 H 2 uptake capacity in addition to good stability. Especially, the optimized SNNU-27-Fe material demonstrates super C 2 H 2 uptake of 182.4 cm 3 g -1 and extraordinary C 2 H 2 /CO 2 dynamic breakthrough time up to 91 min g -1 under ambient conditions, thus outperforms all benchmark MOF adsorbents and represents a promising material for practical C 2 H 2 /CO 2 separation.