Laminar steady buoyancy-driven flow around two interacting isothermal cubes in an infinite medium is investigated by employing a control-volume finite difference technique and holographic interferometry. The two cubes-are positioned along the diagonal direction. Parametric investigations are performed by varying the center-to-center cube spacing and by-varying the Rayleigh number while the Prandtl number is kept constant. To validate the numerical solutions, the calculated isothermal contours are qualitatively compared with the isophase lines in pathlength-integrated holographic interferograms. The heat transfer results are presented in terms of the average Nusselt number and the face average Nusselt numbers al individual walls of each cube.