Synthesis of the bis-4-hydroxycoumarin-type compound, 3,3'-[3-(2-hydroxyphenyl)-3-oxopropane-1,1-diyl]bis(4-hydroxy-2H-chromen-2-one), was performed by two alternative pathways, either involving a basic organocatalyzed 1,4-conjugate addition tandem reaction of 4-hydroxycoumarin on