In this Feature Article, we discuss the variation of optoelectronic properties with the aggregation style of polythiophene (PT) graft copolymers and polymer-modified graphene systems. Grafting of flexible polymers on a PT chain exhibits several self-organized patterns under various conditions, causing different optical and electronic properties, arising from the different conformational states of the conjugated chain. Graphene, a zero band gap material, is functionalized with polymers both covalently and noncovalently to create a finite band gap importing new optoelectronic properties. The polymer-triggered self-assembled nanostructures of PT and graphene-based materials bring unique optical/ electronic properties suitable for sensing toxic ions, nitroaromatics, and surfactants, for drug delivery, and also for fabricating molecular logic gates, electronic rectifiers, photocurrent devices, etc.