Metal-organic coordination compound and method for producing the same

A metal-organic coordination compound, wherein the coordination compound comprises one lanthanide ion coordinated by a polycyclic organic ligand having the formula (1-1) or (1-2)

• with
• L0, L1, L2 being independently each a divalent organic group formed by removing two hydrogen atoms from an organic molecule containing at least two hydrogen atoms, with
• the shortest sequence of atoms in L1, and L2 each linking the two nitrogen atoms adjacent to L1, and L2 being each 4 to 6, which are carbon atoms, with one non-terminal carbon atom of these being replaced by B, N, P, S or O, and with
• R independently in each occurrence representing hydrogen, deuterium, halogen, or a monovalent organic group formed by removing a hydrogen atom from an organic molecule containing at least one hydrogen atom, and wherein any two beta-or gamma-positioned R can be linked to each other to form a ring structure.