A novel host-guest system leading to enhanced luminescence (see Figure) is investigated using a self-forming, solid-state solution of a conjugated polymer. Poly(fluorene-alt-thiophene)s are synthesized with varying ratios of 2,5- and 3,4-thiophene linkages. Small quantities of 2,5-linkages give rise to systems in which a matrix of 3,4-thiophene-linked conjugated polymer transfers electronic excitation energy to isolated, emitting 2,5-thiophene-linked conjugated segments.