polyfunctionalized benzo[ c ]couma-rins were synthesized by a new one-pot reaction of an unprotectedmonohydroxy-3-(acetoacetyl)coumarin as an active methyleneMichael donor with 4-oxo-4 H -chromene-3-carboxylic acid as aMichael acceptor in the presence of a catalytic amount of 4-pyrro-lidin-1-ylpyridine. An organobase-catalyzed tandem 1,4-conjugateaddition, decarboxylation and arom atization reaction mechanism