The adsorption of tris(5,5’-dimethyl-2,2’-bipyridyl)ruthenium(II) ([Ru(dmbpy)(3)](2+))) by a colloidally dispersed montmorillonite or saponite is studied by electric dichroism measurements. [Ru(dmbpy)(3)](2+) is adsorbed up to 100% of the cation-exchange capacity (CEC). An angle (theta) between the threefold symmetry (C-3) axis of a bound chelate and the direction normal to a clay surface is determined from the reduced linear dichroism extrapolated to the infinite field strength. At the loading level less than 13% of CEC, theta is determined to be 54-53 degrees and 57-62 degrees for montmorillonite and saponite, respectively. The results are contrasted with the bindings of [Ru(phen)(3)](2+) (phen = 1,10-phenanthroline) and [Ru(bpy)(3)](2+) (bpy = 2,2’-bipyridyl). These molecules orient the C-3 axes roughly in the perpendicular direction on a clay surface (theta = 16-18 degrees). When the amount of [Ru(dmbpy)(3)](2+) adsorbed is increased to 83%, and 77% of CEC for montmorillonite and saponite, theta decreases to 43-46 degrees and 50-53 degrees, respectively. The changes are ascribed to the intermolecular interactions among the bound molecules. Notably, a definite difference is observed in the dichroism spectra whether the metal complex is adsorbed as a pure enantiomer or a racemic mixture at the higher loading level. These results are compared with the theoretical predictions based on the Monte Carlo simulations.