3,3a‐Dihydrocyclo­penta­[b]­chromen‐1(2H)‐ones from the reaction of salicylaldehyde and 2‐cyclo­penten‐1‐one

The two title chromene compounds, 3,3a‐dihydrocyclo­penta­b]chromen‐1(2H)‐one, C₁₆H₁₂O₂, (I), and 2‐(2‐hydroxy­benzyl­idene)‐3,3a‐dihydrocyclo­penta­b]chromen‐1(2H)‐one, C₁₉H₁₄O₃, (II), have been determined in the monoclinic space group P2₁/n. Compound (I) is mainly stabilized by C—H?π inter­actions. Compound (II) is linked into infinite one‐dimensional chains with a C(3) motif via inter­molecular O—H?O hydrogen bonds. The inter­molecular C—H?π and π–­π inter­actions also play key roles in stabilizing the crystal packing. Two intra­molecular C—H?O hydrogen bonds with S(5) motifs were detected in (II).