TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Halogenating Agents: (a) A halogen X2 or an interhalogen X-X and a base in a mol ratio of (1:1)-(1:100), or an organic bromine complex such as pyridinium perbromide, optionally with a Lewis acid, in a mol ratio of (halogen):(Lewis acid) = (1:0.1)-(1:0.0001); (b) organic N-halogen compounds, or (c) organic O-halogen compounds and halogens X2 in a mol ratio of (0.5:1)-(1:1). The stoichiometric ratio of halogenating agent (based on active halogen content) to the unhalogenated substrate is 2:1, or (3:1)-(1000:1).Preferred Method: The reduction stage may also involve dry heating, under vacuum, of the intermediate Pd(IV) or Pt(IV) compounds isolated in bulk.Preferred Compounds: Compounds (1-8) as above with a purity of more than 99 % (determined by 1H-NMR or HPLC analysis).    TECHNOLOGY FOCUS - POLYMERS - Preferred Polymers: Homo- or co-polymers (P1) with polyfluorene, poly-spirobifluorene, poly-p-phenylene, polycarbazole or polythiophene repeat units, preferably soluble in organic solvents. Preferred Definitions:    L1 = carbon monoxide, tert.-butyl isonitrile, triethylamine, morpholine, trimethylphosphine, triphenylphosphine, trimethyl phosphite, trimethylarsine, triphenylstibine, pyridine etc. (33 ligands listed);    L2 = F, Cl, Br, I, cyanide, cyanate, isocyanate, thiocyanate, ethanolate, phenolate, ethanethiolate, dimethylamide, acetate, trifluoroacetate, benzoate, morpholide, imidazolide etc. (32 ligands listed);    L3 = ethylenediamine, diaminocyclohexane, 2-(1-(2-methylphenylimino)-ethyl)-pyridine, 1,2-bis-phenylimino-ethane, 2,2-bipyridyl, bis-diphenylphosphinomethane, acetylacetonate, pyridine-2-carboxylic acid, glycine, methylsalicylimine, ethylene glycolate, propylenedithiolate etc. (60 ligands listed)    EXAMPLE - A solution of 504 mg bis-(2-(2-pyridyl-kN)-phenyl-kC)-platinum(II) in 200 ml dichloromethane (DCM) was treated in the absence of light with 588 mg N-chlorosuccinimide and 200 micro-l conc. hydrochloric acid, stirred for 20 hours at room temperature (RT), treated with 240 micro-l hydrazine hydrate and 100 ml ethanol, refluxed for 2 hours, concentrated to 20 ml under vacuum, mixed with 200 ml ethanol and worked up by filtration, washing with 3 x 20 ml ethanol and drying at 60 degrees C and 104 mbar, to give 501 mg (87.5 %) bis-(2-(2-pyridyl-kN)-(5-chlorophenyl-kC))-platinum(II) with a purity of more than 99 % (by 1H-NMR analysis).