The cyclotrimerization reactions of enaminones and electron deficient terminal alkynes have been efficiently performed in water in the presence of only a small amount of lactic acid. The reactions led to the green synthesis of a variety of 1,3,5-triacylbenzenes without using any metal as catalyst. Brief investigation on different elaboration of the triacylbenzene product demonstrated the versatile synthetic application of these 1,3,5-triacylbenzenes.