TECHNOLOGY FOCUS - ELECTRONICS - Preferred Devices: Polymeric organic light-emitting diodes, integrated circuits, field-effect transistors, thin film transistors, solar cells, field-quench devices or laser diodes.    TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Catalysts: Palladium, nickel, cobalt or iron, or compounds of these metals.Preferably, the catalyst or its precursor is:(a) a zero-valent palladium compound, especially a tetrakis(triarylphosphine) palladium(0) compound or tris(dibenzylideneacetone) dipalladium(0); or(b) a palladium(II) compound (optionally in presence of at least one ligand), preferably palladium(II) halides, carboxylates or beta-ketoketonates, dichlorobis-(triphenylphosphine)-palladium(II), nitrilopalladium(II) halides, allylpalladium(II) halides and/or olefin-palladium(II) halides; or(c) nickel compounds, especially dispersed or colloidal metallic nickel (supported or not), nickel sponge, nickel on kieselguhr (or on alumina, silica or carbon), nickel(II) carboxylates, ketoketonates, halides, carbonate, nitrate or sulfate, olefin-nickel(II) halides, allyl-nickel(II) halides, addition compounds of formula NiL2(Hal)2, bis-(cyclo-octadiene)-nickel(0), tetrakis-(triphenylphosphine)-nickel(0) or other nickel(0) compounds.L = a neutral ligand;Hal = Cl, Br or IThe palladium catalysts are preferably heterogeneous or immobilised, and are used in presence of additional ligands, e.g. triaryl-phosphines and trialkylphosphines (optionally substituted or otherwise modified), halophosphines or organyloxyphosphines (15 types listed).Preferred Reactants: Bases may be added, preferably alkali or alkaline earth metal oxides, carboxylates, hydrogen-carbonates, phosphates, hydrogen-phosphates, fluorides or alcoholates, organic amines and/or optionally aromatic nitrogen heterocycles.    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Solvents: Aromatic solvents, ethers, nitrogen heterocycles, alcohols, dipolar aprotic solvents, esters, nitrile, amides, halogenated solvents and/or various hydrocarbons.    TECHNOLOGY FOCUS - POLYMERS - Preferred Reactors: Micro-reactors with a capacity of up to 1000 mul, in which the channels have a diameter of 10-2000 microns.Preferred Method: Reactant solutions are pumped in with a flow rate of 0.01 mul/min to 100 ml/min, using two or more micro-reactors in series or in parallel. Reaction is carried out continuously at -80 to +250degreesC, with a residence time of not more than 1 hour, and is monitored and controlled by viscometry. Suitable coupling reactions comprise Suzuki, Yamamoto, Hartwig-Buchwald, Stille, Heck, Sonogashira, Negishi and Hiyama coupling reactions or Grignard cross-coupling.Preferred Process: Polycondensation involves reacting an aromatic compound of formula X-Ar-X (1) with a compound of formula Y-M-Y (2) to give a polymer of general formula -(Ar-M)n- (3), in which:X = Cl, Br, I, fluoroalkylsulfonate or perfluoroalkylsulfonate;Y = X, B(OH)2, B(OR)2, BR2, SnR3, NR-H, MgCl, MgBr, MgI, SiR2F, SiRF2, ZnCl, ZnBr, ZnI, or H (if this is directly attached to a vinyl or acetylenic group in M);Ar = 2-60C arylene or heteroarylene (both optionally substituted with R or OR);M = Ar, or a 1-60C organic group, preferably Ar substituted with vinyl or acetylene group(s));R = H, 1-40C alkyl (linear, branched or cyclic; optionally with one or more non-adjacent C atoms replaced by NR1, O, S, OCOO, COO, -CR1=CR1- or -Ctriple bondC- and/or with one or more H replaced by F, Cl, Br, I or CN) or a 2-60C (hetero)aromatic ring system (optionally substituted with non-aromatic groups R, two or more of which may form another ring system);R1 = H or 1-20C hydrocarbyl (aliphatic or aromatic);n = 10-10000;m = 0 or 1.Alternatively, (3) is formed by the polycondensation of a compound of formula X-Ar-(M)m-Y (4).Reaction is carried out with the addition of water and the amount of catalyst is 0.00001-50 mol.% based on the number of C-C or C-N bonds to be formed. The mixture is worked up by extraction (optionally with complex-formers), by means of ion exchange resins (optionally attached to the reactor wall), or by extraction with mineral acid (all optionally at elevated temperature), and preferably with one or more mixing and separation stages in the micro-reactor. Preferred Definitions: all groups X are identical and all groups Y are identical.