It was found that photopromoted carbonylation of olefins and CO 2 under ambient conditions could be catalyzed by Co(OAc) 2, Co(acac) 2, CoSalen, Cobalt picolinic ester and[Co(14)-4,11-diene-N 4]I 2[5,7,7,12,14,14-hexamethyl-1,4,8,11-tetraazacyclotetradeca-4,11-dieneatocobalt(Ⅱ)]. The carbonylation of cyclohexene gave some by-products of cyclo-C 6H 11-CH 2OH, cyclo-C 6H 11-CHO and cyclo-C 6H 11-COCH 3, which were established by labelling studies with 13CO 2, 13CH 3OH, CD 3OD and CD 3COCD 3. CH 3(CH 2) 7-CH 2OH, CH 3(CH 2) 7-CHO and CH 3(CH 2) 7-COCH 3 were also confirmed as the by-products of carbonylation of 1-octene.