Amino-5-(pyridin-3-yl)-4H-1,2,4-triazole-3-thiol 1 were condensed with 2-bromo-1- (substituted phenyl)ethanone to give pyridinyltriazolothiadiazines 2a~c, which were quaternarized with methyl iodide and oxidized with 30 % hydrogen peroxide to afford the corresponding methyl pyridinium salts 3a~c and pyridine-1-oxides 4a~c, respectively. The reduction of compounds 3 and 4 with NaBH4 in methanol produced the target compounds 1-methyl-1, 2, 5, 6-tetrahydropyridin-3- yl)-6-aryl-s-triazolothiadiazines 5a~c and 3-(1-hydroxyl-1, 2, 5, 6-tetrahydropyridin -3-yl)-6-aryl- s-triazolothiadiazines 6a~c, respectively. The endothelium vascular relaxing activity of the target compounds was screened. Amino-5- (pyridin-3-yl) -4H-1,2,4-triazole-3-thiol 1 were condensed with 2-bromo-1- (substituted phenyl) ethanone to give pyridinyltriazolothiadiazines 2a to c, which were quaternarized with methyl iodide and oxidized with 30% hydrogen peroxide to afford the corresponding methyl pyridinium salts 3a ~ c and pyridine-1-oxides 4a ~ c, respectively. The reduction of compounds 3 and 4 with NaBH4 in methanol produced the target compounds 1-methyl Tetrahydropyridin-3-yl) -6-aryl-s-triazolothiadiazines 5a-c and 3- (1-hydroxyl- 1,2,5,6-tetrahydropyridin- -aryl-s-triazolothiadiazines 6a ~ c, respectively. The endothelium vascular activity of the target compounds was screened.