The templating role of the N,N′-dimethylethylenediammonium (dmedaH2)2+ cation in the synthesis of layered inorganic frameworks has been focused on transition metal hydroselenites and hydrophosphites. Under this work new compounds with the general formula (dmedaH2)[M(HSeO3)2X2] (M = Mn, Co, Cu, Cd; X = Cl, Br) and (dmedaH2)[Mn(H2PO3)2Cl2], which adopt layered structures with distinct hydrogen-bonded motifs, have been synthesized and characterized by single crystal X-ray analysis. The (dmedaH2)2+ cation exhibits a dual role: stabilizing targeted 2D architectures and directing the formation of side products, such as (dmedaH2)[Cd2Cl4(HSeO3)2]·2H2O and (dmedaH2)[Cu(SeO2Br)Br3] (containing rare SeO2Br− anions). Topological analysis reveals the structural complexity and connectivity of these stuctures, highlighting the interplay between cation geometry and inorganic layers. The work underscores the templating potential of dmedaH22+ in designing novel materials, while also demonstrating limitations imposed by steric and electronic factors. These findings advance the understanding of organic-inorganic hybrid systems and their structural diversity.