A non-Kekulé molecule is a conjugated hydrocarbon that cannot be assigned a classical Kekulé structure.
Since non-Kekulé molecules have two or more formal charges or 
radical centers, their spin-spin interactions can cause electrical conductivity or ferromagnetism (molecule-based magnets), and applications to functional materials are expected. However, as these molecules are quite reactive and most of them are easily decomposed or polymerized at room temperature, strategies for stabilization are needed for their practical use. Synthesis and observation of these reactive molecules are generally accomplished by matrix-isolation methods.