The two conformers of acetanilide unraveled using LA-MB-FTMW spectroscopy

► The rotational spectra of acetanilide has been observed using LA-MB-FTMW spectroscopy. ► We have analyzed quadrupole coupling hyperfine structure for trans and cis forms. ► Spectra of cis form is split by tunneling between two equivalent configurations. ► We have compared the results with those of formanilide.