Synthesis and crystal structures of 5,17-di-bromo-26,28-dihy-droxy-25,27-dipropynyloxycalix[4]arene, 5,17-di-bromo-26,28-dipropoxy-25,27-dipropynyloxycalix[4]arene and 25,27-bis-(2-azido-eth-oxy)-5,17-di-bromo-26,28-di-hydroxy-calix[4]arene.

The calixarenes, 5,17-di-bromo-26,28-dihy-droxy-25,27-dipropynyloxycalix[4]arene (CHBrO, ), 5,17-di-bromo-26,28-dipropoxy-25,27-dipropynyloxycalix[4]arene (CHBrO, ) and 25,27-bis-(2-azido-eth-oxy)-5,17-di-bromo-26,28-di-hydroxy-calix[4]arene (CHBrNO, ) possess a pinched cone mol-ecular shape for and , and a 1,3-alternate shape for compound . In calixarenes and , the cone conformations are additionally stabilized by intra-molecular O-H⋯O hydrogen bonds, while in calixarene intra-molecular Br⋯Br inter-actions consolidate the 1,3-alternate mol-ecular conformation. The dense crystal packing of the cone dialkyne is a consequence of π-π, C-H⋯π and C-H⋯O inter-actions. In the crystal of the diazide , there are large channels extending parallel to the axis, which are filled by highly disordered CHCl solvent mol-ecules. Their contribution to the intensity data was removed by the SQUEEZE procedure that showed an accessible void volume of 585 Å where there is room for 4.5 CHCl solvent mol-ecules per unit cell. Rigid mol-ecules of the 1,3-alternate calixarene form a columnar head-to-tail packing parallel to [010] van der Waals inter-actions, and the resulting columns are held together by weak C-H⋯π contacts.