Nonlinear optical properties of synthesized Carbazole based compound (9H-Carbazole-3,6-dicarboxaldehyde, 9-hexyl-) were investigated and measured using Z-scan method with a continuous wave blue diode laser, in different laser intensities. Open aperture Z-scan curves have peak configuration which indicates saturation in absorption has occurred. In close aperture Z-scan measurements, a peak-valley configuration of Z-san curves was related to the thermal-lensing effect that was observed below 100mW incident power. At higher incident powers, because of high nonlinear optical phase change, diffraction rings patterns were observed. Besides the photoluminescence emission of Carbazole compounds under the emission of a blue laser beam, the high nonlinear optical properties of this compound indicate that it can be a potential candidate in optical devices.