Treatments of organic isothiocyanates (R-NCS) with $NaN_3$ in the presence of pyridine in water at room temperature gave corresponding various organic tetrazole-thiones, [$S=CN_4(R)$] (R = alkyl or aryl). Isolated products are obtained as white or yellow solids in good yields (76-97%). The molecular structure by X-ray diffraction study for one of products shows the proposed formation. In addition, one-pot synthesis of 1-substituted 5-alkyl(or aryl)sulfanyltetrazoles has been demonstrated. Addition of alkyl or aryl halides into the mixture of organic isothiocyanates, $NaN_3$, and pyridine in water at room temperature exclusively formed 1-substituted 5-alkyl(or aryl)sulfanyltetrazoles (S-derivatives) in high yields.