One-step thermal processing achieving high-efficiency production of high-performance perovskite hollow fibers (HFs) with precisely controlled cation stoichiometry for ceramic fuel cells, separation membranes and catalytic membrane reactors, is reported by Wanqin Jin and co-workers in article number 1606377. These findings, overturning the traditional production view, provide significantly important progress for perovskite HFs and will potentially push energy-efficient HF-based solid-state devices into industrialized implementation.