AbstractThe photoelectron spectra of bicyclo[3.2.2]nonane and its five dehydrogenated analogues are reported. Analysis of the π‐bands reveals that the unsymmetrical diene 5 retains the ‘natural order’ of the π‐orbitals present in the lower homologues, i. e. the in‐phase below the out‐of‐phase combination of the basis π‐orbitals πaand πc. The isomeric diene4is the first member of the symmetrical homologous series (I), which inverts this order, so thata1(π) (in phase!) lies above