Microwave spectrum and structure of C6H5CCH⋯H2S complex

► Microwave spectra of phenylacetylene···H2S complex and five isotopologues are reported. ► The structure has H2S perpendicular to the phenylacetylene plane with S-H···π hydrogen bond. ► Structure is very different from phenylacetylene···H2O which has H2O in the plane of phenylacetylene. ► Dispersion is not as isotropic a force as commonly assumed.