Some efficient polymer-supported platinum catalysts have been synthesized through the novel application of epoxy resin D.E.R.TM332 cured with polythiourethanes. Epoxide supports were obtained as a result of the use of polythiourethane hardeners. The activity, stability and selectivity during long-term use of the investigated catalytic systems were tested in a hydrogenation reaction of cinnamaldehyde. The results of this study indicate that polythiourethanes used to cure epoxy resin can also greatly affect the catalytic properties of the epoxide-supported platinum catalysts. To fully characterize both polymeric supports and heterogenized catalysts numerous research methods like time-of-flight secondary ion mass spectrometry (ToF-SIMS), infrared spectroscopy (IR), X-Ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM-EDX) and nitrogen BET surface area measurements were used.