We report on the photorefractive properties of polymer composites based on the dye 2, N, N-dihexylamino-7- dicyanomethylidenyl-3, 4, 5, 6, 10-pentahydronaphthalene (DHADC-MPN). At 633 nm and with 2,4,7-trinitrofluorenone as a sensitizer, the polyvinylcarbazole-based composites show complete internal diffraction at applied electric fields as low as E(pi /2) equals 30 V/micrometer. The sensitivity of the composite could be extended into the infrared by using (2,4,7-trinitro-9-fluorenylidene)malonitrile as a sensitizer, and at 830 nm complete internal diffraction occurred at an applied field of Epi/2 equals 59 V/micrometer. Finally, by using DHADC-MPN as a trifunctional dopant in an inert matrix, we have achieved a dynamic range of (Delta) n equals 0.0085 and a net two-beam coupling gain of (Gamma) equals 202 cm-1 at an applied field of 50 V/micrometer and at 633 nm. The composites are thermally stable or have shelf lifetimes of at least several years at room temperature.