Conjugated polymer-based block copolymers (BCPs) have attracted as a great attention for manufacturing nanoscale organic conducting pathway. Herein, we developed a series of poly(3-dodecylthiophene)-block-poly(l-lactic acid) [P3DDT-b-PLLA] that simultaneously contains conjugated block and removable coil block. We successfully formed P3DDT-b-PLLA copolymers microstructures such as lamellar and cylinder including strong crystallization via solvo-microwave annealing. In addition, PLLA block in thin films could be selectively removed using sodium hydroxide (NaOH) solution, followed by a DI-water/MeOH co-solvent washing. Consequently, we could provide strategies for well-defined organic conducting pathway using BCP self-assembly and solution etching process.