Entry Initiator Solvent Yield (%) Mn (kg•mol -1 ) [c] Yields of isolated product after precipitation with methanol (10 mL). Molecular weight and dispersity were determined by GPC in DMF with polystyrene as an internal standard at 50 º C, LiBr/DMF solution (0.01 mol L -1 ) was used as the mobile phase. Initiator (4 mol%). The polymer chain architecture was elucidated using 1 H & C nuclear magnetic resonance (NMR) spectroscopy, which provided evidence for the migration of cyano group within the polymer backbone and the structure of P1 emerging as a sequencedefined polymer with head-to-tail connected (Figure ). The creation of sequencedefined polymers is particularly pivotal in synthetic polymer chemistry as it bestows upon materials bespoke physical properties. For example, the introduction of ethylene moieties enhances both flexibility and resistance to low temperatures, whereas the presence of acrylonitrile units (comprising up to 87% in P1) contributes to the polymer's mechanical strength and chemical resilience. The characteristic aliphatic resonance observed from 2.88 to 3.13 ppm was ascribed to protons H(b, e) situated proximal to the cyano groups. In contrast to the monomer, the aliphatic resonance typically around 4.79-4.71 ppm assigned to He became undetectable. Organic elemental analysis (EA) quantified the elemental constituents of the polymers (C: 69.97%, H: 6.71%, N: 23.31%), mirroring the calculated percentages for the repeating unit. Verification of the cyano group in the polymer was corroborated by its showing chain-growth behavior.