In　this　study,　quinoid　structures,　semiquinone　radical　structures,　and　electron　affinity　energies　(EAEs)　of　many　polycyclic　quinones　containing　heteroatoms　(O,　B,　and　F)　or　heterocycles　(pyrrole,　imidazole,　and　pyrazine)　were　calculated.　Quinones　with　unstable　quinoid　structures　and　stable　semiquinone　radical　structures　had　high　EAEs.　The　main　factors　of　quinoid　structural　instability　were　spatial　repulsion　and　antiaromaticity,　and　the　stability　factors　of　the　semiquinone　radical　structure　comprised　inductive　effects,　hydrogen　bonds,　electrostatic　in-teractions,　and　orbital　interactions.　Compound　11　had　both　the　antiaromaticity　of　the　quinoid　structure　and　the　orbital　interactions　of　the　semiquinone　radical　structure,　thus　having　the　highest　EAE.　The　crystal　structure　of　compound　8　was　obtained,　and　it　confirmed　the　reliability　of　the　calculated　results　of　this　work.