The application of thiirane resin cured with polythiourethane (PTU) hardeners as novel and efficient support for palladium complex catalyst is reported. Stability and activity efficiency in Heck reactions were determined. IR and X‐ray photoelectron spectroscopy provided information of metal coordination to the polymer matrix. Characterization of polymer supports and palladium catalysts has involved the measurements of the structural parameters in the dry state by the nitrogen BET adsorption, time‐of‐flight secondary ion mass spectrometry, scanning electron microscopy, and energy dispersive X‐ray analysis. The results of this study indicate that PTU used to cure thiirane resin can greatly affect the catalytic properties of the episufide resin‐supported palladium catalyst. These new type of polymer supports comparing to other organic carriers offers several practical advantages such as ability to control the crosslinking density, porosity and the chemical structure of the polymeric matrix, which influence the catalytic properties of the immobilized metal complex. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40330.