`Rod-coil' block copolymers with poly[2,7-(9,9-dialkyl)fluorene] (2,7-PF) blocks as the rod segment and poly(ethyleneoxide) blocks as the flexible coil segment has been developed to combine the photophysical properties of conjugated polymers with supramolecular ordering of block copolymers. In order to balance the electron and hole injection in light-emitting devices (LEDs), poly[2,7-(9-fluorenone)] (2,7-PFO) with low and reversible reduction potential ( −1.48 V) has been synthesized as electron-injection/hole-blocking material. Ladder-type poly( para-phenylene) (LPPP) is one of the mostly favored materials for blue LEDs, since the polymer is fully soluble, structurally well-defined and exhibits high photoluminescence quantum effeciency. Spectral narrowing of the PL emission was observed at pumping pulse energies in the blue of <5 μ J/ pulse. LPPP films spun on a nanostructural DFB resonator can act as single-mode blue–green solid-state lasers, so-called `plastic lasers'. To bridge the gap between LPPP and 2,7-PF, novel poly[2,8-(6,6,12,12-tetraalkyl)indenofluorene]s (2,8-PIF) have been synthesized, that exhibit an efficient blue photoluminescence and thermotropic liquid crystallinity above 250 ° C.