Oblon, Spivak, McClelland, Maier & Neustadt
Tetraazaporphyrins and optical recording medium
 An optical recording medium contains tetraazaporphyrins of the formula ##STR1## where L.sup.1, L.sup.2, L.sup.3 and L.sup.4 are each independently of the others the radical of a bicyclic aromatic heterocycle containing 1 to 3 identical or different heteroatoms selected from the group consisting of N, O and S, which may be substituted, and PA0 R.sup.1 and R.sup.2 have defined meanings. 
BASF Aktiengesellschaft
C C C G C G Y
C09B C07F C07F G11B C07F G11B Y10S
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Peter Rolf-Dieter Bernhard
Neumann Kohler Albert