This paper examines the impact of chemical reaction, radiative heat transfer, and mass transfer on unsteady magnetohydrodynamic (MHD) Casson fluid flow including heat generation and viscous dissipation passing a vertical porous plate. The fluid is taken to be incompressible and electrically conducting, thermal radiation being modelled by the Rosseland approximation. The equations of state that are governing, nonlinear partial differential equations of momentum, energy, and concentration, are postulated under the Boussinesq approximation and scaled into dimensionless equations using appropriate similarity transformations. The ensuing coupled set of equations is numerically solved by the Crank Nicolson finite difference method. The influence of the different physical parameters on velocity, temperature as well as concentration profile is analyzed and discussed with the help of graphical and tabular analysis of the physical parameters which include Casson parameter (β) and thermal Grashof number (Gr), solutal Grashof number (Gc), radiation parameter (R), Prandtl number (Pr), Schmidt number (Sc), chemical reaction parameter (Kc), heat generation parameter (Q) and Eckert number (Ec). Moreover, the skin friction coefficient, Nusselt number and Sherwood number have been calculated and tabulated. The findings also indicate that radiation and chemical reaction have significant effects on thermal and concentration boundary layers and heat generation and viscous dissipation improves the velocity and temperature fields. The research is helpful in applications to industrial cooling, polymer processing, geothermal energy mining and chemical engineering process using non-Newtonian Casson fluids.