Cover Picture (Angew. Chem. Int. Ed. Engl. 3/1986)

The cover page shows the skeleton (white) of porphycene, a novel aromatic isomer of porphin (gray) with effective D 2h symmetry, which is determined by extremely rapid NH‐tautomerism. This fascinating pyrrolic macrocycle, which dissolves in organic solvents to give blue solutions showing beautiful red‐violet fluorescence, is, despite its—in comparison to porphin—much smaller cavity, capabable of forming metalloporphyrin‐ and metallophthalocyanine‐type complexes. In the light of the intensively studied chemistry and biochemistry of the porphyrins it seems remarkable that porphycene and its derivatives, for which a host of interesting applications can be envisaged, could have remained concealed for such a long time. Further details are reported by E. Vogel et al. on page 257ff.