The reaction of dialkyl acetylenedicarboxylates with 4-hydroxyquinoline in the presence of triphenylphosphine (20 mol-%) produces dialkyl (Z)- and (E)-2-(4-hydroxyquinolin-3-yl)-2-butenedioates in good yields. When the reaction was performed with 2-methyl-4-hydroxyquinoline, similar (E)- and (Z)-isomers were obtained.