<p>The present study focuses on the dynamic thermal degradation kinetics of a series of trimellitimide (TMI) derived epoxy-imide (EI) resins incorporating aliphatic, cycloaliphatic, and aromatic moieties, compared with triglycidyl isocyanurate (TGIC). Isoconversional kinetic analysis was performed on non-isothermal thermogravimetric data to obtain the dependence of activation energies (<i>E</i>_<i>α</i>) on conversion (<i>α</i>). Given the multistage nature of the degradation processes, mathematical deconvolution analysis (MDA) was employed to separate overlapping thermal events. The reaction model analysis indicated that each stage follows a quasi-autocatalytic (quasi-AC) mechanism. Accordingly, reaction orders were determined using the truncated Šesták–Berggren model. Our findings demonstrated that in all EI systems, autocatalytic characteristics increased with the progress of degradation, while <i>n</i>th-order behavior diminished. The intensity of these fluctuations was inversely related to the melting temperature of the base resins, following the trend in diglycidyl esters: 1,6-hexamethylene bis(TMI) &gt; 1,3-bis(methyl-TMI) benzene &gt; 1,3-bis(methyl-TMI) cyclohexane.</p>