The results of investigation of molecular association in liquid crystalline α-cyanostylbenes are reported. The dielectric dispersion of α-cyanostylbenes and it solutions doped weakly polar nematic mixture are investigated. The real and imaginary parts of dielectric permitivities ε_| and ε_⊥ of solutions with several concentrations have been measured in frequency range 1kHz-100MHz. The one dispersion region of ε_| and ε_⊥ of pure α-cyanostylbenes were observed. In contrast to pure α-cyanostylbenes two separate dispersions of Debye type were found for parallel component of the dielectric permitivity ε_| for solutions.