Semiconducting poly(3-aminophenylboronic acid) (PABA) and poly(thiophene-3-boronic acid) (PTBA) nanoparticles are synthesized using KIO3 and (NH4)(2)S2O8 as initiators, respectively; and structural, morphological, and surface characterizations are carried out by various well-known techniques. Electrokinetic properties of PABA and PTBA dispersions are determined by zeta (zeta)-potential measurements in aqueous medium by taking the effects of pH, various electrolytes, surfactants, and temperature into account. Colloidally stable range of +30 mV <= zeta <= -30 mV is obtained in the presence of NaCl and Na2SO4 for PABA and PTBA, respectively. Addition of anionic surfactant, sodium dodecyl sulfate, to PABA and PTBA dispersions shifts the zeta-potentials to more negative values and enhances their colloidal stabilities. zeta-Potential values of PABA increase with rising temperature, whereas almost no change is observed for PTBA at elevated temperatures up to 65 degrees C. zeta-Potentials of PABA and PTBA dispersions in silicone oil with the absence and presence of Triton X-100 are also determined to be high.