Two-dimensional unsteady laminar double-diffusive free convective flow of a conducting fluid in a thermally insulated square enclosure except the left wall has been numerically studied in presence of heat generation/absorption. The Marker and Cell (MAC) method is employed for solving non-linear momentum, energy and concentration equations and the numerical MATLAB code is validated with the previous study. The computed results are depicted graphically and discussed for various values of Rayleigh number (Ra), Hartmann number (Ha), Buoyancy ratio parameter (N), Lewis number (Le) and heat absorption/generation parameter ( ). It is observed that the rate of heat and mass transfer decreases with increasing Rayleigh number.