Selenium assisted carbonylation of alkyl aryl ketones with carbon monoxide leading to formation of 1,3-dicarbonyl compounds as C-carbonylated products is described. o-Hydroxyacetophenone 7a and its derivatives7b,7c, and 7d have been converted to the corresponding 4-hydroxycoumarins 8a,8b,8c and 8d in moderate to quantitative yields by treatment with an equivalent of selenium and carbon monoxide with