[Display omitted] New thermally stable long-chained 2-alkylisothiuronium 7-chloro-4,6-dinitrobenzofuroxan-5-olates were obtained from the corresponding bromides and 5,7-dichloro-4,6-dinitrobenzofuroxan, the hydrolysis of the C(5)–Cl bond to produce phenolic function having occurred in the course of the process. The compound structure was determined by IR spectroscopy, elemental analysis and X-ray single crystal study. Salts with C 14 –C 18 alkyl groups revealed moderate antibacterial and antifungal activities. [ABSTRACT FROM AUTHOR]