The investigation of the catalytic activity of [RhA(CO)(2)] (HA; anthranilic acid) and its polymer analogue [Rh(OOCC6H4 NHCH2-P)(CO)(2)]; P = polystyrene moiety, towards the reductive carbonylation of nitrobenzene in DMF medium has been reported. The maximum yield and selectivity of diphenylurea was achieved using methanol as cosolvent under optimum reaction conditions. Spectroscopic and kinetic studies showed that the reaction proceeds through a species [RhA(O)OCH3)(2)] and the isocyanate formed at an intermediate stage is immediately scavenged by excess amine to form N,N'-diphenylurea. A tentative reaction mechanism based on the identification of reactive intermediates has been proposed for the carbonylation process. (C) 2002 Elsevier Science B.V. All rights reserved.