The kinetics of reactions between benzaldehyde and diethyl acetylenedicarboxylate with para-substituted anilines for the one-pot formation of 3,4,5-substituted furan-2(5H)-ones have been studied spectrally at different temperatures in formic acid. For all substituents at the para position of the aniline ring, the reaction followed second-order kinetics. The partial orders with respect to substituted aniline and diethyl acetylenedicarboxylate were one and one, and the reactions also revealed zero-order kinetics in relation to benzaldehyde. Para-electron donating substituents on the aniline ring increased the rate of reaction. On the basis of experimental data, a three step mechanism has been proposed. Kinetic values (k and E_a) and associated activation parameters (ΔH^≠, ΔG^≠ and ΔS^≠) of the reactions were determined.