A light emitting device having at least one layer that contains a
phosphorescent organometallic dendrimer with a metal cation and two or
more coordinating groups as part of its core and wherein at least two of
said coordinating groups each have a dendron attached, at least one of
which dendrons comprises at least one nitrogen atom which forms a part of
an aromatic ring system or is directly bonded to at least two aromatic
groups.