This communication describes a new method that enables high yield assembly along both of the two-dimensional edges of DNA origami tiles by controlling the Mg(2+) concentration; high Mg(2+) concentrations promote linkage connections between the vertical edges of the tiles. As a demonstration, DNA origami dimers assembled from two rectangular origami along the vertical edges are used as scaffolds for the double sided assembly of gold nanoparticles with different inter-particle spacings.