Recent studies on the cis-and trans-1,2-dibenzoylethylenes and benzalacetophenones (2-4) are of interest in connection with the possibility of assignment of configurations to the alkoxy, aroxy, hydroxy, amino, and alkylaminodibenzoylethylenes (I, II, VIII, IX), and have led to the further work described in this paper.Methoxydibenzoylethylene (I) (5-9), known in only one form, has been regarded (probably correctly) as thermodynamically the more stable of the two possible stereoisomers, and because of this it was considered to be trans (7). However, its synthesis by nitric acid oxidation of the corresponding furan suggests the cis configuration (9, 10).Positive evidence on which to base configurational assignments was sought through study of cases where both stereoisomers could be obtained and compared. 1 The work On which this paper is based is described in ref.(1).