Abstract: A Steady 2’ D flow of graphene-water Casson nanofluid due to a stretching/shrinking sheet is examined. The thermal radiation and heat source/sink parameters effects are considered. Utilizing similarity transformations, the nonlinear PDE’s are converted into a nonlinear ODE’s with reduced boundary conditions. Hence, the exact analytical solutions have been deduced. A theoretical result was apparatus to survey on axial and transverse velocities, temperature, reduced skin friction and local Nusselt number with suitable parameters. It is examined that when the values of thermal radiation, volume fraction, injection and Eckert number, increases then the graphene nanoparticles behave like a heater. And also they behave like cooler when the values of magnetic field, suction, primary and slip secondary Navier’s slip and heat source/sink increases. The present work containing engineering and industrial applications such as manufacturing of plastic and rubber sheets, annealing and thinning of copper wires, extrusion of polymer etc. Also, in the present analysis graphene nanoparticles can be used as a heater on increasing the solid volume fraction, injection, thermal radiation and Eckert number. On the other hand, they act as a cooler with an increase of magnetic field, suction, first velocity slip, second velocity slip and heat source/sink. Graphical abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer Nature India Private Limited.