Aromatize: Transforms the molecule from Kekulé representation to aromatic representation by using the general aromatization method.
Dearomatize: Transforms the molecule from aromatic representation to Kekulé representation. (This method does not check by default if Hückel's rule is valid.)
For pressing the button successively, the function converts the structure from Kekulé to aromatic form back and forth. If there is a selected aromatic ring on the canvas, Aromatize/dearomatize method works only for the selected structural part.
(This tool requires JChem Web Services.)