Phthalocyanine derivatives, which have a similar structure to porphyrin, have been utilized in
important functional materials in many fields. Their useful properties are attributed to their efficient
electron transfer abilities. The central cavity of phthalocyanines is known to be capable of
accomodating 63 different elemental ions, including hydrogens (metal-free phthalocyanine, H2-PC). A
phthalocyanine containing one or two metal ions is called a metal phthalocyanine (M-PC). In the last
decade, as a result of their high electron transfer abilities, M-PCs have been utilized in many fields
such as molecular electronics, optelectronics, photonics, etc [1-6] (Figure 1). The functions of M-PCs
are almost universally based on electron transfer reactions because of the 18 electron conjugated
ring system found in their molecular structure.