In the Research Highlight 'Molecular materials: Persistent porosity' (Nature Chem. 6, 1028; 2014), the penultimate sentence of the second paragraph should have read: 'Those sheets are in turn held together through interlayer π–π stacking interactions between the electron-rich pyrazole units and the comparatively electron-poor fluorinated aromatic rings'. This has been corrected in the online versions after print 25 November 2014.