We have succeeded in the synthesis of dihydropyrazinefused porphyrin dimers through oxidation of beta-aminoporphyrins. The structure of the dimer was revealed by X-ray diffraction analysis, showing its saddle like conformation. Optical and electrochemical analysis was conducted to elucidate the properties of the dimers. The theoretical calculation suggested that the electron-donation from the dihydropyrazine nitrogen atoms to the porphyrin pi-plane was weakened due to its distorted conformation.