As intercalated oxidant (guest) is chemically de-intercalated stepwise from poly(3-octylthiophene) (P30T) (host), a gradual evolution of a mat-type crystalline structure is observed. Moreover, the intercalated oxidant has marked effect on the arrangement of polymeric chains. Complete thermal de-intercalation of oxidant leads to interwoven cylindrical bundles of polymeric chains similar to corrugated-rod-type (CRT) morphology seen for thermally annealed pristine P30T. The red shift along with increase in intensity and sharpness in UV-vis spectra and photoluminescence quenching indicate that the ripening of the self-assembling nature of pristine P30T polymer leads to the formation of polymeric quasi-crystals when it is freed from oxidant impurity chemically or by prolonged soft-thermal annealing of oxidant intercalated polymer matrix. The present results enable the analysis of the effects of geometrical parameters characterizing the mutual host-guest complementarity as well as host-guest and guest-guest interactions on the crystal packing of intercalate. (c) 2006 Elsevier B.V. All rights reserved.