Electronic spectroscopy of the cis and trans isomers of 1-methyl-2-phenylcyclopropane

► Electronic spectra of the jet-cooled cis and trans isomers of 1-methyl-2-phenylcyclopropane have been recorded. ► The trans isomer adopts a bisected conformation in both ground and excited electronic states. ► Electronic excitation induces a large torsional geometry change in the sterically hindered cis isomer.