Poly­(butylene succinate) (PBSu) and poly­(ethylene adipate) (PEA), isomeric to each other, are mixed in a miscible state, and PBSu crystallized at T c’s where PEA is kept at a molten state. PBSu upon crystallization in the presence of isomeric PEA at various Tc’s develops sector-face spherulitic patterns, which are shown to originate from a common nuclei center. The two faces of sector-face PBSu spherulites are more strikingly contrast when PBSu is highly diluted by isomeric PEA in PBSu/PEA mixtures (PEA = 70–80%) and crystallized at intermediate T c = 50–60 °C. The main characteristics of crystallized PBSu and lamellar assembly mechanisms in these two faces were investigated using POM, SEM, AFM, and DSC. For both faces (ring-banded vs dendritic) of the sector-face PBSu spherulites, the lamellar assembly mechanism differs, but the growth is similar by repeating with periodic multiplication of fractal branches (whose number is proportional to square of radius) in the next cycle; thus, the lamellae fractal branches not only able to interpret the periodic optical banding but also account for filling the expanding spherulite. This growth mechanism is readily accounted by many fractal patterns in the nature.