This book displays how optical (absorption emission and magnetic circular dichroism) spectra
of phthalocyanines and related macrocyclic dyes can be varied from their prototypical ones
depending on conditions. As these compounds can be involved in colorful chemistry (which might
be driven by impurities in solvents) their spectra behave like the sea-god Proteus in their
mutability. Therefore those who have been engaged with phthalocyanines for the first time
including even educated professional researchers and engineers may have been embarrassed by
the deceptive behavior of their compounds and could have in the worst cases given up their
projects. This book is aimed not merely at reviewing the optical spectra but also at helping
such people particularly beginners to figure them out by showing some examples of their
prototypical spectra and their variations in several situations. For the purpose of better
understanding the book also provides an introduction to their theoretical backgrounds as
graphically as possible and without mathematicization for readers who are weak in mathematics.
