Despite various studies to obtain structural insight into spin-casted molecular doped organic semiconductors, our understanding of polymer-dopant interactions during the spin-casting process is limited. In this work, we have employed a combination of experimental and theoretical studies to reveal heterogeneous ion-pair interactions in precursor solution mixtures of prototypical P3HT/F 4 TCNQ system in chlorobenzene as a case study. The two-dimensional electronic spectroscopic measurements captured the electronic interactions amongst the ionpair via unique signatures of the off diagonal coupling peaks. In addition, the dynamics of the D 1 state of F 4 TCNQ anion showed bi-exponential dynamics with time constants of ∼30 and ∼200 fs (instead of expected mono-exponential decay), signifying the presence of heterogeneity with in the interacting ion-pairs. With the help of MD simulations on 1:1 solution mixtures of P3HT/F 4 TCNQ in chlorobenzene and quantum chemistry calculations on selected configurations, we have obtained three dominant interaction modes with different excitonic coupling strengths: 75 cm -1 for side-chain, 150 cm -1 for π-π-stack, and 69 cm -1 for slipped stack. Interestingly, the MD trajectory have also shown the presence of transient long-range interactions with a π-stack configuration in the modeled solution mixture. Thus, our study provides a detailed analysis of the possible nature and strengths of electronic interactions amongst ion-pair in precursor solutions of P3HT/F 4 TCNQ in chlorobenzene. It will be interesting to explore how these seed-interactions evolve during the spin-casting process, and what physical parameters dictate the retention of one interaction mode over other in films. We envision that capitalizing on this quantitative structural understanding of the seed-interactions in precursor solutions, one may think of possible ways to achieve desirable interactions in the spin-casted films, and hence improve the doping efficiency.