Bowl-shaped pi-conjugated compounds including partial structure of fullerenes, which are called "buckybowls", are of importance not only as model compounds of fullerenes but also as their own chemical and physical properties.  Two pristine structure are known, C_5v-symmetric corranulene and C_3v-symmetric sumanane. One of the characteristic features of buclybowls is that they possess terminal C-H structure, which can be chemically transfered to the functional groups to control the chemical/physical structure of the bowls with ease. In particular, three benzylic positions of sumanene are highly expected to functionalize to other groups such as carbonyl group, which can tune the electrochemical character of the bowls. For example, sumanenetrione exhibits stepwise multi-electron reduction process.  Cyclic voltammograms of the stepwise first and second one-electron reduction showed reversible waves with associated reduction potentials which were almost equivalent to those of C₆₀.