The heat and mass transfer characteristics of the unsteady electrically conducting fluid flow past a suddenly started vertical infinite flat plate are taken into account in this paper. The radiation and heat absorption/generation effects for two distinct types of thermal boundary conditions are accounted for. Derivation of exact analytical solutions are aimed under different physical properties. The velocity, concentration and temperature profiles, skin friction coefficient, Sherwood number and Nusselt number are easily examined and discussed via the closed forms obtained. In particular, the Sherwood and Nusselt numbers are found evolve into their steady state case in the large time limit. The results obtained here may be further used to verify the validity of obtained numerical solutions for more complicated transient free convection fluid flow problems. (C) 2012 Elsevier Ltd. All rights reserved.