Molecular and crystal structure of 4-ethynylcyanobenzene. An example of CH⋯N hydrogen bonding

The molecular and crystal structures of 4-ethynylcyanobenzene are reported. The packing of molecules in the crystal is found to be homologous with the crystal structures of HCN, cyanoacetylene and 4-cyano-4′-ethynylbiphenyl. Alternatively, these four crystals could be said to constitute a structural homologous series. The influence of CH⋯N hydrogen bonding in directing a linear supramolecular arrangement of molecules with ethynyl and cyano groups at opposite ends, is illustrated.