Although aromaticity is widely used in explaining the “extra stability” of a particular class of organic compounds, it has not been properly defined. It is subsequently extended to several other systems including inorganic and all-metal systems. Hence, an aromatic moiety with extraordinary stability can act as a promising building block for various nanomaterials. In this chapter, we present aromaticity in various all-metal and nonmetal systems, and the hydrogen (H2) storage potential of different novel molecular templates composed of aromatic units. A thorough analysis is carried out to understand the effect of H2 binding on the aromaticity of the template and vice versa. Whereas aromaticity is assessed through the study of various energetic, geometrical, magnetic, and reactivity criteria, H2 binding ability is evaluated by computing the related binding energy. The construction of temperature-pressure (T-P) phase diagrams for various systems highlights T-P regions where the adsorption or desorption of H2 would be favorable. Furthermore, the effect of an external electric field on improving the H2 binding ability of a template is explored.