This dataset supports the publication: Computational and spectroscopic characterisation of thianthrene, (Rachel H. Rushworth, Matei Pascariu, Mona Sarter and Stewart F. Parker, Royal Society Open Science (2024)). The dataset consists of a README file (README_Parker_Thianthrene_dataset.txt), two zip files: "A-Experimental_spectra", "B-CASTEP". and an image file: Thianthrene_Mode_at_862cm.jpg. The README describes the contents of the archive. A-Experimental_spectra.zip contains the DSC data and the infrared, Raman and inelastic neutron scattering spectra. B-CASTEP.zip contains the input and output files for the calculation of the complete unit cell and the C2v symmetry isolated molecule.