Three azolo[b]1,3,4-thiadiazinium bromides were prepared from the respective N-amino-N'-methylazolethiones and phenacyl bromide, and their crystal structures were determined. 6-Phenyl-1-methylimidazo[2,1-b]1,3,4-thiadiazinium bromide (1) crystallized as methanol solvate (P21/n), 6-phenyl-1-methyl-1,2,4-triazolo[3,4-b]1,3,4-thiadiazinium bromide (2) as hemi-ethanol solvate (P21/n), and 6-phenyl-...