TECHNOLOGY FOCUS - POLYMERS - Preferred Components: The metal cluster anion has the following formula: (MaQbXc) raised to d-.M=metal atoms of the metal cluster;a=2-20, preferably from 2 to 8;Q and X=ligands, Q representing a face-capping ligand or an edge-bridging ligand, and X representing an apical ligand;b=2-30, preferably from 8 to 12;c=2-50, preferably from 2 to 6; andd=1-12, preferably 2 to 4.The cationic head is selected from an imidazolium, a pyridinium, a pyrolidinium, an ammonium, a phosphonium, a hydroxyphosphonium or a sulfonium; in which the pyrolidinium, ammonium, phosphonium, hydroxyphosphonium or sulfonium can be further substituted by one or two 1-3C alkyl groups. The substituent comprises a terminal part and a linker having from 1 to 30 methylene groups, the terminal part being the polymerisable functional group and the linker linking the terminal part to the cationic head. At least one of the methylene groups of the linker is replaced by one or more atoms or groups of atoms selected from aromatic rings, -O-, -CO-, -S-, -CH=CH-, ethynynlene, -COO-, -OC(O)-, -CH=N-, -CH=N-, -C(O)NH-, -N=N-, -NH(CO)- and its mixtures. At least one of the hydrogen atoms of the linker are replaced by fluorine atom. The polymerizable functional group is selected from double carbon-carbon chemical bond, triple carbon-carbon chemical bond, an azide function, a methacrylate function, acrylate function, an amine function, a carboxylic function, an aldehyde function, a hydroxyl function, an alkoxy function, an iodine atom, a bromine atom and a chlorine atom. The organic cation is further substituted by a second substituent containing from 1 to 30 methylene groups. At least one of the methylene groups of the second substituent is replaced by one or more atoms or groups of atoms selected from aromatic rings, -O-, -CO-, -S-, - CH=CH-, ethynylene, -COO-, -OC(O)-, -CH=N-, -CH=N-, -C(O)NH-, -N=N-, -NH(CO)-and its mixtures. At least one of the hydrogen atoms of the second substituent is replaced by a fluorine atom. The luminescent salt comprises formula I.P1=cationic head, selected from an imidazolium, a pyridinium, a pyrolidinium, an ammonium, a phosphonium, a hydroxyphosphonium or a sulfonium;P2 and P3=substituents, where P2 comprises a terminal part and a linker having from 1 to 30methylene groups, the terminal part being the polymerisable functional group and the linker linking the terminal part to the cationic head, preferably, at least one of the methylene groups of the linker is replaced by one or more atoms or groups of atoms selected from aromatic rings, -O-, -CO-, -S-, -CH?=CH-, ethynylene, -COO-, -OC(O)-, -CH=N-, -CH=N-, -C(O)NH-, -N=N-, -NH(CO)- (or rather -NH-CO-) and its mixtures, preferably, at least one of the hydrogen atoms of the linker are replaced by a fluorine atom, and/or preferably, the polymerisable functional group is selected from double carbon-carbon chemical bond, triple carbon-carbon chemical bond, an azide function, a methacrylate function, acrylate function, an amine function, a carboxylic function, an aldehyde function, a hydroxyl function, an alkoxy function, an iodine atom, a bromine atom and a chlorine atom; where P3 contains from 1 to 30 methylene groups, preferably, at least one of the methylene groups of P3 is replaced by one or more atoms or groups of atoms selected from aromatic rings, -O-, -CO-, -S-, -CH=CH-, ethynylene, -COO-, -OC(O)-, -CH=N-, -CH=N-, - C(O)NH-, -N=N-, -NH(CO)- and its mixtures;z=0-12, preferably from 1 to 3;n=1-12, preferably 1 or 2;g=1-4; andf=1-12 and equals d/g.Preferred Composition: The polymeric material comprises up to 60 wt.% of the luminescent salt, preferably up to 50wt.%, still preferably 5 to 50 wt.%, more preferably about 10 to 50 wt.%, weight percentage being given with respect to the total weight of the polymeric material. Preferred Definitions:    Q=either a halogen, a chalcogen, and its mixtures; and    X=at least one element selected from fluorine, chlorine, bromine, iodine, carbon, nitrogen, sulfur, boron, oxygen, hydrogen and its mixtures.    EXAMPLE - No suitable example given.