Hydrazinium 5-nitrimino-1H-tetrazolate (1) and dihydrazinium nitriminotetrazolate monohydrate (2) were synthesized by the reaction of hydrazine with 5-nitriminotetrazole. The energetic compounds 1 and 2 were characterized by single-crystal X-ray diffraction (only 2), NMR spectroscopy, IR- and Raman spectroscopy as well as DSC measurements. The sensitivities towards impact, friction and electrical discharge were determined. In addition, several detonation parameters (e.g. heat of explosion, detonation velocity) were computed by the EXPLO5 computer code based on calculated (CBS-4M) heats of formation and X-ray densities.