Theoretical calculations have been carried on four compounds, bicyclo[4.1.0]heptan-7-one cis and trans, 2-cyclohepten-1-one and cycloheptenyl cation to determine their UV, IR and NMR spectra (chemical shifts). In the case of the known 2-cyclohepten-1-one the agreement is satisfactory. Predictive properties have been calculated for the elusive bicyclo[4.1.0]heptan-7-one cis molecule.