2,2-Dinitroethene-1,1-diamine (FOX-7) is an insensitive, energetic material with a simple structure but very unusual properties. With interest among chemists in expanding the chemistry of FOX-7, continuous efforts are underway to improve the performance of the compound by modifying and optimizing its structure and creating various derivatives. In this Review, the chemical reactivity of 1,1-diamino-2,2-dinitroethene (FOX-7) towards nucleophilic (transamination), and electrophilic substitution, and its acid–base properties are explored as well as an account of the molecular structure, physical and detonation properties of derivatives, salts and metal complexes of FOX-7.