The photoluminescence and electroluminescence of guest-host blends containing DD and DDD (see Figure) in the conjugated polymers polyvinylcarbazole (PVK) and poly[2-methoxy-5-(2'-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) is described. It is shown that this class of long-wavelength-emitting porphyrin oligomer, is an excellent platform upon which to fabricate near-infrared light-emitting devices.