Abstract: A halogen containing compound is coupled in the presence of carbon monoxide, an alkaline medium and a supported palladium catalyst. The reaction is preferably effected at elevated temperature and pressure, for example 80.degree. C. to 200.degree. C. and 0.2 to 3MNm.sup.-2. The alkaline medium can be aqueous sodium hydroxide solution. The support of the supported palladium catalyst may be calcium carbonate or charcoal. The halogen containing aromatic compound can be, for example, chlorobenzene; 4-chlorotoluene; 4-methoxychlorobenzene; 4-chlorophenol; 4-chlorobenzoic acid; 4-chloro-4'-hydroxybenzophenone; 4-bromobenzoic acid; 4-bromophenol; 2-chlorotoluene; 2-hydroxy-5-chlorobenzoic acid or 2-chloropyridine. Some of the resulting compounds or derivatives thereof are novel, such as 4,4'-bis(4-acetoxybenzoyl) biphenyl, which is useful as an intermediate for preparing polyesters and polyethers.