Dope dyeing of filaments/fibers has gained considerable interest in academics as well as in the industrial community in recent years due to the intrinsic dyeing of polyester during fiber spinning. It has altogether good physical and chemical properties than exhaust dyed material. The use of dope-dyed polyester yarn is preferred in certain specific application areas like Army uniforms due to its higher fastness properties. In this context, it has also been realized that dope dyed polymer gives less burden to the environment. Despite this, the textile processors might compromise on this front because of a marginal increase in cost. Therefore, exhaust dyeing is still popular in the textile wet processing industry not only due to its lower cost and easy accessibility but also have much more choices of different colors, unlike dope dyeing where only fiber/filaments manufacturer have their choices with a limited number of color pigments. The polyester fabric of the same color but produced by dope and exhaust-dyeing routes looks similar. However, the performance of the dope dyed and exhaust dyed polyester fabric in terms of color fastness to various chemical agents and environmental conditions is different. This difference in fabric performance may create shade-off or a tonal variation, which creates hurdles to achieve desired long-term properties. However, there is no standard method available to distinguish exhaust or dope dyeing methods of polyester fibers/fabrics. Efforts are being made in this direction, but no confirmative result has been reported yet. Therefore, there is a necessity to develop a standard method to understand whether the sample is dope dyed or dyed using the exhaust dyeing route. The current project covers a systematic investigation of the dope dyed and exhaust dyed polyester filaments/fabrics through physical, chemical, optical, thermal, microstructural, and morphological studies.