A series of novel 6-aryl-3-(1,2,3,4-tetrahydroxybutanol-1-yl)-7H-1,2,4-triazolo[3,4-b][1,3,4]thiadiazines were easily synthesized in high yields by means of the reactions of 4-amino-5-(1,2,3,4-tetrahydroxybutyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione (1) with substituted ω-bromoacetophenones or ω-chloroacetophenone. Nearly all of the title compounds possess plant growth-promoting activities.