1?4,2,4,6-thiatriazines were identified as a novel class of herbicides. Their interesting effects on plants as well as their uncommon structures incited further studies. In addition to the initial sulfodiimine based preparation method, a flexible synthetic route was designed giving access to a larger array of compounds. The poor initial biological activity was improved and compounds with very high herbicidal activity were identified. Thiatriazines have been found to be unique and very potent inhibitors of the biosynthesis of cellulose, which is a major component of the plant cell wall. While the precise biochemical site of thiatriazine action is not yet known, they are known to induce the formation of a non-crystalline ?-1,4-glucan, as opposed to previously described herbicides which inhibit cellulose biosynthesis. Studies on the uptake, translocation and metabolism of a representative thiatriazine provided evidence for crop selectivity on the basis of differential rates of metabolism in various plant species.