Abstract The synthesis of supramolecular polymers (SPs) with controlled architecture is a grand challenge in supramolecular chemistry. Although living supramolecular polymerization (LSP) via primary nucleation has been extensively studied for controlling the supramolecular polymerization of small molecules, the resulting SPs have typically exhibited one-dimensional (1D) morphology. In this report, we present the synthesis of intriguing SP architectures through a secondary nucleation event, a mechanism well-established in protein aggregation and the crystallization of small molecules. To achieve this, we selected perylene diimide with 2-ethylhexyl chains (2EH-PDI) at the imide position and stabilized its dormant monomers in solution. Activating these dormant monomers via mechanical stimuli (self-seeding) and hetero-seeding using propoxyethyl PDI (PE-PDI) seeds, secondary nucleation event takes over, leading to the formation of 3D spherical spherulites and scarf-like SP heterostructures, respectively. Therefore, the results presented in this study propose a simple molecular design for synthesizing well-defined SP architectures via secondary nucleation.