Flexible hydrogen-bonded organic frameworks (FHOFs) are quite rare but promising for applications in separation, sensing and host-guest chemistry. They are difficult to stabilize, making their constructions a major challenge. Here, a flexible HOF (named 8PN) with permanent porosity has been successfully constructed. Nine single crystals of 8PN with different pore structures are obtained, achieving a large-scale void regulation from 4.4% to 33.2% of total cell volume. In response to external stimuli, multimode reversible structural transformations of 8PN accompanied by changes in luminescence properties have been realized. Furthermore, a series of high-quality co-crystals containing guests of varying shapes, sizes, aggregation states and even amounts are obtained, showing that 8PN can adapt to different guests by regulating the molecular conformations and assembling forms of its building blocks. The unexpected flexibility of 8PN makes it a promising material for enriching the applications of existing porous materials.

柔性氢键有机骨架（FHOF）非常罕见，但有望用于分离，传感和客体化学中。它们难以稳定，使其结构成为主要挑战。在这里，已经成功地构造了具有永久孔隙率的柔性HOF（命名为8PN）。获得了九个具有不同孔结构的8PN单晶，实现了从总细胞体积的4.4％到33.2％的大规模空隙调节。响应于外部刺激，已经实现了伴随着发光性质变化的8PN的多模可逆结构转变。此外，还获得了一系列高质量的共晶，其中包含形状，大小，聚集状态甚至数量各不相同的客体，表明8PN可以通过调节其构象的分子构象和组装形式来适应不同的客人。8PN出乎意料的灵活性使其成为一种有希望的材料，可以丰富现有多孔材料的应用。