Simple aromatic molecules may be precursors for polycyclic aromatic hydrocarbons in space, and some of the simplest ones are now detected in the earliest stages of star formation . Evidence of benzonitrile (C6H5-CN) in the interstellar medium  questions the presence of related aromatic nitriles and their ring-chain derivatives. In light of previous work  on phenylpropiolonitrile (C6H5-C3N), we are investigating, by laboratory high-resolution studies, its ethynylbenzonitrile (HCC-C6H4-CN) derivatives where a -CN and a -CCH groups lie in ortho (2-ETB), meta (3-ETB) or para (4-ETB) positions.
The pure rotational spectrum of these compounds has been recorded at room temperature in the millimeter-wave domain using a chirped-pulse W-band (75–110 GHz) spectrometer. To facilitate spectral assignments, quantum chemical calculations have been performed using density functional theory at the $\omega$B97X-D/cc-pVQZ level of theory (geometry optimization, harmonic frequencies).
We will report a description of the experimental set-up and of our assignment procedure.
 A.Burkhardt et al., Nature Astronomy 5, 181-187 (2021)
 McGuire et al., Science 359, 202-205 (2018)
 Z.Buchanan et al., Journal of Molecular Spectroscopy 377, 111425 (2021)