Epitaxial growth of thiophene/phenylene co-oligomers (e.g., see Figure) on uniaxially oriented poly(p-phenylene) (PPP) is reported. The emission properties of these co-oligomer thin films are investigated and compared to those of films grown on quartz. Color-tunable emission highly polarized along the direction of orientation of the PPP is observed in the former case, while isotropic emission occurs on the quartz substrate.