Al(4)(2-) was the first discovered σ + π aromatic all-metal cluster. In the present work we analyze the molecular structure, relative stability, and aromaticity of lowest-lying isomers of related M(2)N(2)(2-) (M and N = B, Al, and Ga) clusters, with special emphasis devoted to the cis (C(2v)) and trans (D(2h)) isomers of the M(2)N(2)(2-) clusters. For such purpose, we start by performing the search of the global minimum for each cluster through the Gradient Embedded Genetic Algorithm (GEGA). Energy decomposition analyses and the calculated magnetic- and electronic-based aromaticity criteria of the lowest-lying isomers help to understand the nature of the bonding and the origin of the stability of the global minima. Such methodology should allow guiding future molecular design strategies.