𝐞𝐪. 𝟒 Above one-particle wavefunction series are plotted in Figure , obviously, they correspond well with the one-particle spatial molecular orbitals and therefore give a correct chemical image for the electronic structure of in-plane and out-plane π-systems in cyclo-[2n]-carbon. By extending particle in a box to the ring condition, this presentation is easy to understand, on the basis of the particle in a box model. We then move on determine which model can better describe the electronic structure of cyclo-[2n]-carbon.