The structural and electronic properties of alkannin and its derivatives and their radicals were investigated at density functional level. It turned out that the presence of the dihydroxy functionality increases the radical stability through hydrogen bond formation and favors hydrogen atom abstraction. The introduction of electron-donating groups for the molecules increases the activities of antioxidants. Moreover, alkannin and its derivatives appear to be good candidates for the one-electron-transfer mechanism. Their extended electronic delocalization between adjacent rings determines low ionization potential (IP) values, and it can be further improved by the introduction of the electron-donating groups for the molecules.