Phthalocyanine (Pc) is a beautifully symmetrical 18 p-electron aromatic macrocycle, closely related to the naturally occuring porphyrins. Like the porphyrins, the Pc macrocycle can play host to over seventy different metal ions in its central cavity. Since its discovery over seventy years ago, Pc and its derivatives have been extensively used as colorants (dyes or pigments). More recently they have been employed in several 'hi-tech' applications such as the photoconducting material in laser printers and the light absorbing layer in recordable CDs. They are also used as photosensitisers in laser cancer therapy, as nonlinear optical materials and as industrial catalysts. The synthesis and applications of Pc materials is a very dynamic and multidisciplinary field of research.