A new core expanded calix[4]pyrrole is reported, in which the opposite bridging sp3-carbons are replaced by ethylene moieties. This macrocycle forms a unique helical pattern and binds to two water molecules, forming an infinite 1D chain synergistically stabilized through hydrogen bonding with the two outwardly projected pyrrolic NHs of the calixpyrrole.
![Graphical abstract: 1D water chain stabilized by meso-expanded calix[4]pyrrole](http://hg.y866.cn/compound/lib/scimg/usr/1/C4CE01502A.jpg)