In this study, different dithiol/dimethacrylate formulations +/- octamethacryl-polyhedral oligomeric silsesquioxanes (POSS) were synthesized and fully characterized in terms of structural, morphological, and thermostability features. The obtained results indicate that the incorporation of both dithiol and octamethacryl-POSS nanofillers within dimethacrylate matrix exhibits a significant influence on the surface chemistry, polymerization kinetics, thermostability, and thermomechanical properties of the resulting networks. Kinetic analysis showed that the presence of dithiol compound improves the conversion degree of the final dithiol/dimethacrylate networks, while thermal and thermomechanical analyses exhibit that octamethacryl-POSS produces nano-hybrids with enhanced thermostability and storage moduli.