3,4,5,6,7,8,9-Heptachlorophenaleno[1,9-bc]pyrazole

Treatment of perchloro-7H-cyclopropano[a]acenaphthylene 1 with hydrazine hydrate in DMF at ca. 80 °C gives the new 3,4,5,6,7,8,9-heptachlorophenaleno[1,9-bc]pyrazole 2 in 69% yield. This compound is the first example of a phenalene fused pyrazole.