Poly(alkyl benzoate)s were prepared by the coupling of alkyl dichlorobenzoates with zerovalent nickel generated in situ from nickel(II) bromide and characterized by H-1 NMR spectroscopy. While the spectra of the substituted poly(p-phenylene)s were complicated by the irregular distribution of substituents and the flipping of the phenylene rings, the spectra of poly(m-phenylene) derivatives were simple. In the spectra of poly(dodecyl-p-phenylene), the relative positions of the two signals due to the cu-methylene group, associated with head-to-tail and head-to-head bondings of the phenylene rings, were reversed upon the introduction of the methoxycarbonyl group. The poly(alkyl benzoate)s melted under microscopic observation and thermally decomposed in two stages. The decomposition temperature ranged from 380 to 460 degrees C for the first stage and from 550 to 590 degrees C for the second stage. These findings indicated that these polymers were soluble, fusible and thermally stable. The poly(alkyl benzoate)s were hydrolysed and decarboxylated to the corresponding polyphenylenes. Although the substituted poly(p-phenylene)s were easily converted to polyphenylenes, the poly(m-phenylene) homologues were resistant to hydrolysis.