A simple and efficient method has been developed for remarkable rate acceleration and yield enhancement of the Baylis–Hillman reaction under solvent-free “neat conditions” and solvent-less isolation of products. Reaction of equimolar quantities of aldehyde and olefin in the presence of 20 mol% of DABCO under neat conditions affords the highest yield in most cases within the shortest reaction time, giving support to the mechanisms of proton transfer in protic and aprotic solvents. Solvent-free conditions are found to be especially fast, selective, and high yielding for aromatic aldehydes.