The reaction of 2,4-disubstituted thiosemicarbazides with 2,3,5,6-tetrachloro-1,4-benzo-quinone gave 2-aryl-5,6-dichloro-3-(substituted imino)-2,3-dihydro-1 H-indazole-4,7-diones in 57–66% yield together with smaller amounts of 2-aryl-3-(substituted imino)-4,6,7-trichloro-2 H-indazole-5(3 H)-ones (21–25% yield). Reaction of 2,3-dichloro-1,4-naphthoquinone with 2,4-disubstituted thiosemicarbazides provided 2-aryl-3-(substituted imino)-2,3-dihydro-1 H-benzo[ f]-indazole-4,9-diones in 63–74% yield. Rationales for these transformations are presented.