Noble metal-free TADF molecules offer unique optical and electronic properties arising from the efficient transition and interconversion between the lowest singlet (S) and triplet (T) excited states. Their ability to harvest triplet excitons for fluorescence through facilitated reverse intersystem crossing (T →S) could directly impact their properties and performances, which is attractive for a wide variety of low-cost optoelectronic devices. .Poly(ethylene 2,6 naphthalate) (PEN) is a reported polymer of naphthalene-2,6-dicarboxylate and ethylene glycol, having excellent heat resistance, enhanced dimensional stability and demonstrating electroluminescence involving physical processes such as charge injection, extraction, transportation and chemical reaction through excited states. In the present study, the derivatives of PEN derived from the chain elongation n =1, 2,3,4,5 named as monomer, dimmer, trimmer, tetramer and pentamer etc, have been taken up for the investigation of various optoelectronic properties including the thermally activated delayed fluorescence (TADF) by using the Koopmans Method and Density Functional Theory, executed in Schrödinger Software and depicted in the findings. The present study suggests the utility of the dimmer and trimmer as a suitable TADF material for flexible Electronics applications.