In this article we have studied the photophysics of an alkaloid harmaline in 1,4-dioxane-water mixtures. It was known that the microstructure of this binary mixture changes upon varying the mole fraction of 1,4-dioxane in mixture. We have observed that the photophysics of harmaline in 1,4-dioxane-water mixtures is modulated with change in mole fraction of 1,4-dioxane in the binary mixture. We have observed some interesting changes in the photophysical parameters of harmaline in 1,4-dioxane-water mixtures as a function of the mole fraction of 1,4-dioxane. (C) 2018 Elsevier B.V. All rights reserved.