Anodic oxidation of the model bilindione (1) at platinum electrodes in the presence of methanol gives a good yield of the 15,16-dimethoxybilindione (3). With nickel(II) acetate, this compound gives the chelate (6) which fragments upon treatment with acid toafford the tripyrrinone aldehyde (2)via the vinyl ether (8). When the metal-free 15,16-dimethoxybilindione (3) is treated with aqueous acid the same tripyrrinone aldehyde (2) to gether with the parent bilindione (1) are obtained.