Heteroatom rich 1,2,3-dithiazoles are relatively underexplored in medicinal chemistry. We now report screening data on a series of structurally diverse 1,2,3-dithiazoles and electronically related 1,2,4-dithiazines with the aim of identifying interesting starting points for potential future optimisation. The 1,2,3-dithiazoles, were obtained via a number of different syntheses and screened on a series of cancer cell lines. These included breast, bladder, prostate, pancreatic, chordoma and lung cancer cell lines with an additional skin fibroblast cell line as a toxicity control. Several low single digit micromolar compounds with promising therapeutic windows were identified for breast, bladder and prostate cancer. Furthermore, key structural features of 1,2,3-dithiazoles are discussed, that show encouraging scope for future refinement.