We present an experimental study of the photorefractive effect in a multifunctional carbazole trimer sensitized with 2,4,7‐trinitro‐9‐fluorenone. The trimer consists of a central carbazole ring which is conjugated with two 6‐dicyanovinylcarbazoles through ethynylene groups. It exhibits intrinsically photocarrier transporting, electro‐optic, film‐forming, and room‐temperature poling properties. Photorefractive effect at a wavelength of 633 nm was demonstrated by measuring the phase shift of refractive index and asymmetric energy transfer in a two‐beam coupling experiment. A large net photorefractive gain coefficient (Γ‐α) of 76/cm was obtained in a sensitizer‐optimized material. A four‐wave mixing experiment was carried out to measure the magnitude of index modulation and dynamics of the grating formation. © 1996 American Institute of Physics.