The discovery of aromatic stabilization for [18]annulene is historically significant for confirming earlier theoretical predictions based on molecular orbital theory, since simple versions of valence bond theory did not readily explain 4n + 2 rule.

The 1H NMR of this compound exhibits hallmarks of a system with an aromatic ring current, with the 12H signal of exterior hydrogens at 9.25 ppm, while 6H signal of interior hydrogens resonates at a remarkable −2.9 ppm in THF-d8 at −60 °C.

For comparison, these values are close to bond length of benzene (140 pm).

Nevertheless, it rapidly undergoes electrophilic additions, much like other polyenes, and attempts to effect Friedel-Crafts type reactions on [18]annulene failed.

[6] The original synthesis started by Eglinton reaction of di-alkyne 1,5-hexadiyne with copper(II) acetate in pyridine to give the trimer, followed by deprotonation and isomerization with potassium tert-butoxide in tert-butanol and was concluded with hydrogen organic reduction with Lindlar catalyst.