Treatment of vic-dihydroxyindeno[1,2-d]imidazoles with N,N,N’,N’-tetraalkyl sulfurous diamides yields indeno[1,2-d]imidazoles by deoxygenation. Isochromeno[3,4-d]imidazoles are formed as byproducts. An X-ray crystal structure analysis confirmed the structure of deoxygenated products. The ratio of products depending on the reaction conditions was analyzed. A mechanism of the reaction is discussed.