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Reduction of anti-1-benzoylanthraquinone oxime gave 2-phenylanthra[9,1-bc]pyrrol-6-one whose structure was determined by X-ray analysis. The molecule of 2-phenylanthra[9,1-bc]pyrrol-6-one is almost planar, and its crystalline structure is characterized by head-to-tail chains formed via intermolecular hydrogen bonds N-H · · · O. 9,10-Anthraquinone derivatives attract strong interest for both science and technics. They are traditionally used for the manufacture of synthetic dyes, but in the recent time 9,10-anthraquinones have found new applications, in particular as biologically active compounds, analytical reagents, luminophores, components of liquid crystalline compositions, photographic materials, etc.[1]. The 2-phenylanthra[9,1-bc]pyrrol-6-one system (A) is a peri-fused antrhaquinone derivative with 1,10-anthraquinoid structure. The presence of a fused pyrrole ring and anthrone fragment with unusual ana-quinoid bond configuration suggests high reactivity of such system.First attempts to synthesize anthra[9,1-bc]pyrrol-6-ones with no substituent on the nitrogen atom were reported long ago. Sholl et al. [2] showed that anthra-[9,1-bc]pyrrole derivatives can be obtained by reduction of 1-aroylanthraquinonone oximes. However, the products were assigned anthroxyl radical structure B, and later, aminyl radicals C [3]. According to [4, 5], such radicals are generated by reduction of 1-cyanoanthraquinone or in the cyclization of 1-aminomethyl derivatives of 2-hydroxyanthraquinone which are obtained in turn by alkaline hydrolysis of 1-phthalimidomethyl-or trichloroacetylaminomethyl-2-hydroxyanthraquinones. After repeated experiments, Sholl and Muller [6] concluded that the reduction products of 1-aroylanthraquinone oximes are non-radical species and that they have structure A with 1,10-anthraquinoid bond distribution; however, no rigorous proofs for the