The efficient synthesis of a novel cyclic carbazole tetramer and carbazole main-chain polymer via the Knoevenagel condensation has been developed. The carbazole cyclic tetramer could be obtained in a high yield by a one-stage Knoevenagel condensation of 3,6-diformyl-9-heptylcarbazole and 3,6-bis(cyanoacetoxymethyl)-9-heptylcarbazole in tetrahydrofuran (THF) without the use of the high-dilution principle. The corresponding carbazole main-chain polymer could also be obtained as a main product by a two-stage Knoevenagel polycondensation. Detailed structural characterization of this novel oligomer by spectroscopy and elemental analysis confirmed the cyclic structure. The corresponding main-chain polymer with large molecular weight was found to be amorphous by differential scanning calorimetry. Studies on the nonlinear optical and photorefractive properties of these materials are in progress.