TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Component: The organometallic dendrimer can be of formula (M-(X(DENDRITE(-Q)n)y)xYz. It contains partially conjugated dendron(s) or dendritic molecular structure comprising aryl and/or heteroaryl groups or nitrogen and, optionally, vinyl or acetylenyl groups via sp2 or sp hybridized carbon atoms of the (hetero)aryl, vinyl or acetylenyl groups via single bonds between N and (hetero)aryl groups, CORE terminating in the first single bond that is connected to an sp2 hybridized (ring) carbon atom of the first (hetero)aryl group or nitrogen to which partially conjugated dendritic branch is attached, the ring carbon atom, or N forming part of the DENDRITE. The surface groups in the dendrimer allow solution processing or patterning. The DENDRITE is attached to a coordinating group X that is bonded to M via the metal-carbon bond.x = at least2 preferably 3;y = at least2;z = 0.Preferred Composition: The molar ratio of organometallic dendrimer to the other component(s) is 1:1-100:1. The additional component represents 95-5 mol.% of the total composition.Preferred Property: The dendrimer emits charge transfer rate from a metal to ligand.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Component: The metal cation is iridium, rhenium, or platinum.    TECHNOLOGY FOCUS - IMAGING AND COMMUNICATION - Preferred Component: The light-emissive layer is a film comprising an organometallic dendrimer. It comprises an emissive dopant, molecular or dendritic species, or polymer as additional component. The device also includes a charge-transporting layer. Preferred Definition:    Q = further-reactable alkene, (meth)acrylate, sulfur-containing or silicon-containing group, sulfonyl group, polyether group, 1-15C alkyl, amine, mono, di, or tri 1-15C alkyl amine, COOR group (where R is H or 1-15C alkyl), OR (where R is H, aryl or 1-15C alkyl or alkenyl), SR (where R is aryl or 1-15C alkyl or alkenyl), or SiR3 group (where R is H, 1-15C alkyl or alkenyl), or SR' group (where R' is aryl or 1-15C alkyl or alkenyl) aryl, or heteroaryl.    EXAMPLE - A mixture of ligand 4-(3'5'-Di(4''-(2'''-ethylhexyloxy)phenyl)-2-(3''''-(3'''''5'''''-di(4 ''''''-(2'''''''-ethylhexyloxy)phenyl)phenyl)phenyl)pyridine (200 mg), iridium (III) acetoacetate (12.4 mg), and glycerol (1 cm3) was degassed and then heated with a heating mantle at 220degreesC for 14 hour. The mixture was allowed to cool to ambient temperature and dissolved into acetone (8 cm3) and DCM (sic) (3 cm3. The solution was left to stand and the layer containing the dendrimer was separated from the glycerol layer. The mixture was evaporated to 4 cm3 and purified over silica gel using light petroleum as eluent to give 9 mg (10%) yellow orange solid of Fac tris (4-(3'5'-Di(4''-(2'''-ethylhexyloxy)phenyl)-2-(3''''-(3'''''5'''''-di( 4 ''''''-(2'''''''-ethylhexyloxy)phenyl)phenyl)phenyl)pyridine)iridium (III).