Owing to the potential applications of nanostructures consisted of conjugated polymers (CP), the self-assembly of the CP is taking the spotlight in the supramolecular chemistry field. Also, one of the most important requirements for the applications, the precise control of the shape and size of the structures is essential. Fortunately, through interesting crystallization-driven self-assembly (CDSA) for well-known crystalline polymers reported by Manners group first, we have successfully controlled the size of various multidimensional nanostructures. However, only a few examples of living one-dimensional (1D)- or two-dimensional (2D)-CDSA for crystallizable CPs have been reported in spite of their high potential as functional optoelectronic materials. Based on our early investigations on the living cyclopolymerization, we designed new crystalline P1 homopolymer containing a fluorene moiety with bulky neohexyl groups on monomer units. To prepare fully conjugated block copolymer (BCP) including P1 as the second block, we polymerized soluble first block (P2) followed by polymerizing P1. To fully investigate the structural properties of the structures, we used various microscopes and X-ray diffraction analysis. As results, we achieved to form two-dimensional (2D)-nanosheets from the P1 homopolymer with the tunable height. By expanding the P1 to the BCP (P2-b-P1), we also succeeded in the formation of rigid 1D-nanoribbons with tunable length and width via 1D-CDSA. More recently, we have succeeded in producing the uniform monolayer 2D-nanosheets from the 2D-CDSA of P1 for the 2D-rectangular micelles by blending the crystallizable polymers. Those unique fluorescent semiconducting nanostructures with tunable shapes are potentially useful in optoelectronic applications.