The solution-phase morphology and dynamics of the organic semiconducting polymer P(NDI2OD-T2) was studied using coarse-grained molecular dynamics simulations in order to understand the reported formation of extended rod-like aggregates in poor solvents. We found that sufficiently strong intermolecular attractions (equivalent to poor solvent quality), for which interaction through only a few monomers resulted in effectively inseparable chains, led to the build up of extended aggregates of partially overlapping chains with radii of gyration exceeding that of a single chain. Over time, a trend towards more linear, rodlike aggregates was also observed, consistent with experimental results. We proposed that this behaviour, which is not predicted by existing theories of polymer solubility, in which decreasing solvent quality is conventionally associated with the formation of com- pact aggregates, is a kinetic effect associated with the relative rates of multi-chain aggregation and single-chain folding. The formation of extended aggregates is expected under conditions in which aggregation occurs faster than folding, assuming interchain attraction is strong enough to hold chains together in an only partially overlapping chain configuration. Firstly, we showed that under conditions that correspond to P(NDI2OD-T2) in the poor solvent toluene, at concentrations representative of experiments in which rod-like aggregates were observed, aggregated chains overlapping by only around 40% of their full chain length were stable over the duration of the simulations. Under conditions corresponding to a better solvent, this overlap fraction increased over the entire simulation duration, and was expected to reach close to the full chain length. This finding is consistent with the difference between the experimentally observed behaviour in good-intermediate and poor solvents, with rod-like aggregates observed in the poor solvents, and structures in the better solvents showing sizes consistent with single chains, despite some aggregation occurring, suggesting almost fully overlapping chains.