Thermal, mechanical, and electrical characterization. We further investigate the material properties including T g (by differential scanning calorimetry [DSC] and dynamic mechanical analyzer [DMA]), tensile strength, dielectric properties, coefficient of thermal expansion (CTE), and thermal stability (by thermogravimetric analysis (TGA)) (Table ). Varying the diallyl imide monomer results in a range of T g values from 66 to 92 °C (Figure ). T g values measured via DSC are slightly lower than those from DMA but confirm the same relative trends (Figure ). Notably, the stiff aromatic PI's, PI hexafluoro and PI diether, resulted in the highest T g values while the aromatic PI's containing flexible linkages of the PI ester and PI ether had the lowest T g values (Figure ). Observing such a structure-property relationship in these networks confirms a high fidelity between our polymer design, synthesis, and processing. From DMA, PI-cyclohexane has the highest rubbery modulus of 7.2 MPa which suggests an average molecular weight between crosslinks (M c ) of 1440 g mol -1 which is in alignment with PI-cyclohexane possessing the lowest molar mass (Figure ) (M c calculations can be found in the SI). PI-hexafluoro shows the lowest rubbery modulus (3.4 MPa) and the highest M c of 3920 g mol -1 , in agreement with the higher molar mass of the bisimide molecule. From Figure , the measured Young's moduli range from 1180 MPa to 1330 MPa, with the ultimate tensile strength ranging from 46 MPa to 56 MPa (Table ). The polymers exhibit moderate extensibility, with elongation-at-break values around 6%, except for PI-ether with an elongation-at-break of 47%, likely due to its flexible ether linkage providing additional backbone mobility. While these physical properties are lower than commercially used polyimides, typically these have undergone rigorous process optimization and have additives to give them their robust toughness. We conclude that all five thiol-ene poly(imide ester) networks are mechanically robust and very capable of serving as e-substrates and with additional formulation and additives allowing for a more direct comparison to commercial polyimides.