A light-emitting photoresist comprising a vinyl-ether-based photosensitive polymer host doped withstar-shaped π-conjugated truxene–core oligomers is shown to be a promising platform for therealization of soft-matter photonic devices. In particular, a simple processfor the fabrication of free-standing membranes with no spin casting andpeel-off steps is reported. The approach uses instead the hydrophobic natureof the nanocomposites. Membranes are fabricated, with a concentration of 20 mg ml − 1 of the truxeneoligomer denoted as T3, directly on deionized water by ultraviolet flood illumination. The resulting membrane is 94 µm thick onaverage with a diameter up to 50 mm. Amplified spontaneous emission developing around 435 nm abovean ∼ 400 µJ cm − 2 threshold is obtained by optical pulse pumping the sample at 355 nm in an edge-emittingphotoluminescence configuration. These membranes form a versatile platform for flexibleorganic semiconductor lasers and optical amplifiers.