Abstract: The present invention relates to a process for the preparation of sublimable oligomers based on phenylene, linear and of controlled length, by electrochemical coupling of two lower oligomers within a monocompartmental cell with three electrodes, in the presence of an organometallic catalyst, characterized in that it comprises:1--electrolysis of the catalyst and its reaction with one of the two oligomers at a first potential,2--reduction of the insertion species obtained according to step 1, and its reaction with a second oligomer at a second potential below the first potential, and3--recovery of the sublimable oligomer so obtained, the two lower oligomers used being mono- or dihalogenated oligomers identical or different.The present invention also relates to sublimable oligomers based on phenylene obtained by this process, and their uses in electronics and/or optics.

Abstract: The invention relates to a method of manufacturing a film of polyparaphenylene by electro-polymerization, the method being the type using electrochemical reduction of a monomer having the following formula: ##STR1## where n is an integer lying in the range 1 to 4, the method taking place in an electrochemical cell (1) including a reference electrode (4), a working electrode (2), and a counter electrode (3), said electrodes being immersed in an electrolyte including one or more aprotic solvents, at least one of which is bipolar, and an anhydrous background salt in the presence of an organometallic catalyst of the NiX.sub.2 L type where X is a halogen and L is a binder, the working electrode being a solid cathode and the catalyst/monomer ratio lying in the range 0.1 to 1.