Luminescent semiconducting oligomers (LSOs) have been one of the most popular molecular materials that can be applied in various fields because of their distinctive optical properties. The study of molecular packing and morphological change of oligomers is essential for the rational design of materials and regulation functions. Herein, we report two novel LSOs (OFBB and OFBT) with a slight difference in chemical structures but show a distinct difference in self-assembly behaviors in the coordination-driven process. OFBB forms spherical particles with Zn(II). Compared with OFBB, OFBT has an additional thiazole moiety, which forms spherical particles with Zn(II) and then transforms to a crystalline nanobelt in 2 h. The process and mechanism of the nanosphere and nanobelt formation were investigated in detail. The double S···N interaction between two benzothiazoles in adjacent oligomers played a significant contribution in this dynamic morphology transformation. In addition, the as-prepared two products showed excellent sensing toward nitrobenzene with good selectivity over other nitro-aromatic explosives.