Donor–acceptor (D–A) copolymers having strong intermolecular interaction induced aggregation can exhibit far higher mobilities compared to the homopolymers and, thus, are preferred as active layers for optoelectronic devices. However, the actual performances of such devices strongly depend on the conjugation length, i.e., backbone planarity or exciton bandwidth (EB) and edge-on oriented (EO) ordering of the copolymer aggregates and, thus, their understanding and improvement are of paramount importance, which were carried out here using complementary techniques such as optical absorption spectroscopy, X-ray reflectivity, and atomic force microscopy and by tuning the pre-deposition parameters such as solvent, polymer concentration (c), and spinning speed (ω) of the spin-coated D–A copolymer thin films. The high c-value films show unusual improvement of EB with increasing ω, unlike low c-value films, for the first time. The overlapped and entangled aggregates, which are known to form in the high c-value solution of high viscosity, get disentangled in the film during deposition due to a large centrifugal force arising from their relatively large effective mass along with the increasing ω-value. On the contrary, the well separated less entangled aggregates, which formed in the low c-value solution of low viscosity, get entangled in the film due to the ω-related fast evaporation of the solution. Ultimately, improved EB is observed when both c and ω are either small or large for the films prepared using chlorobenzene (CB) and only large for the films prepared using chloroform (CF), which can be realized considering effective evaporation rate and viscosity of the solutions during deposition, while improved EO ordering is found when both c and ω are small (i.e., when diffusion and organization of aggregates are easy) for the films prepared using both the solvents. Altogether, the films prepared using CF with high c and ω values show crystallites with high EB but low EO ordering, while those with low c and ω values show better EO ordering but low EB. The films prepared using CB with low c and ω values show improvement of both EB and EO ordering, and thus expected to provide better device performances compared to others.