The packing of the two crystallographics forms the 2-hydro nitronyl nitroxide (HNN) molecule has been studied. Using the ab initio methodology described in the accompanying paper, the packing is rationalized. In both crystals the primary structure are the HNN dimers linked trough C(sp2)-H...O-N contacts. These dimers form planes of molecules, which constitute the secondary structure. The structure and stability of the planes are different in the two crystals. Finally, the planes form stacks, the tertiary and last structure in both crystals. The forces involved in each type of structure have been quantified. The relationship between the two polymorph crystal forms have been analyzed and rationalized.