Abstract9‐Phenyl‐1,2,3,4,5,6,7,8‐octahydrodibenzo‐γ‐pyran (V) was obtained from the mother liquor of crude 2,6‐dibenzylidenecyclohexanone (DBH) (1).Oxidation of 2,5‐dibenzylidenecyclopentanone (DBP) and DBH yielded benzoic and succinic acids, and benzoic, glutaric and 2‐benzylideneadipic acids respectively. Chromic acid oxidation of DBH gave benzaldehyde and benzoic acid, while that of the DBH dimer did not yield either of the two products.The formation of the DBH dimer by refluxing DBH in ethanol was inhibited by acid, alkali, rubber stopper, and sulfur, but was not affected by soft glasswares.Two dimers and three monomeric isomers of DBH were isolated, two of them probably represent cis forms.Thermal isomerization and dimerization of dibenzylideneacetone, difurfurylideneacetone, and difurfurylidenecyclohexanone were also studied. The latter two compounds were failed to give even a trace of the expected isomers or dimers.DBH gave, with phenylhydrazine, 2,3‐diphenyl‐7‐benzylidenecyclohexa‐pyrazoline (XII), while DBP with the same reagent at 190‐200° afforded benzaldehyde phenylhdrazone, ammonia, and water. The tetra‐bromide of DBP (XV) and phenylhydrazine readily gave