ring enlargement to cinnolines. Reaction with 2-bromo-2,3-dihydro-1Η-inden-1-one gives a 4-hydroxyspiro[cinnoline-3,2'-inden]-1'-one by ring enlargement reaction (X-ray crystal structure analysis). Vicinal dibromides undergo debromination under these conditions to give alkenes, and substrates with 1,2-dibromoethene partial structure give acetylenes. As 3-bromoindazole is found as the second product of