This paper explore the Marangoni boundary layer flow in a Casson nano liquid over a stretching sheet. The effect of chemical reaction and uniform heat source/sink are taken into the account. The standard nonlinear system is resolved numerically via Runge-Kutta based shooting scheme. Role of substantial parameters on flow fields as well as on heat and mass transportation rates are determined and conferred in depth through graphs.From the investigation it reveals that, the Marangoni number plays a connecting role between the velocity and temperature gradients on the boundary surface. Further,the higher values of Lewis number and chemical reaction parameter reduces the solutal thermal boundary layer thickness decreases.