In the present study, reactivity base-catalyzed hydrolysis of 7-dimethylamino-4-methyl-
2H-chromen-2-one (DMAC) and 7-diethylamino-4-methyl-2H-chromen-2-one (DEAC) in binary
aqueous–methanol and aqueous–acetone mixtures was examined at 298 K. Kinetic results, rate laws
and reaction mechanisms were established. Moreover, the change in the activation energy barrier of
the investigated compounds from water to water–methanol and water–acetone mixtures was estimated
from the kinetic data. Base-catalyzed hydrolysis of (DMAC) and (DEAC) in aqueous–methanol
and aqueous–acetone mixtures follows a rate law with kobs= k2[OH]. The decrease in the rate
constants of (DMAC) and (DEAC) as the proportion of methanol and acetone is due to the destabilization
of OH ion. The solubilities of the studied compounds, DMAC and DEAC in water 
methanol and water–acetone mixtures were established and their transfer chemical potentials were
calculated. Solvent effect on reactivity trends of the investigated compounds has been analyzed into
initial and transition state components by using the transfer chemical potentials of the reactants and
the kinetic data of the studied compounds. The decrease in the observed rate constant values (kobs)
of the base hydrolysis of DMAC and DEAC with increasing of methanol% or acetone% is dominated
by the initial state (IS).