The reaction of lithium phenylacetylide with phenyl isothiocyanate followed by the addition of ethanol produces a crystallographically-characterised heterocycle formed by the cyclisation of two molecules each of acetylene and isothiocyanate, and which is identical to the dimer of the acetylenic thioamide PhCbond; length of mdash" data-inlimg="/entities/tbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">CC(bond; length as m-dash" data-inlimg="/entities/dbnd" src="/sd/grey_pxl.gif" class="glyphImg imgLazyJSB">S)NHPh, described almost a century ago.