© 2018 Bentham Science Publishers.Background: Aromatic polyamides are important materials having outstanding thermal, electronic and mechanical properties among high performance polymers and industrial plastics. In addition, aromatic polyamides can be utilized in electronic devices with their low dielectric constant which indicates the storage capacity of these devices. Objective: Free volume is very important for dielectric materials and increase in free volume of a polymer reduces its dielectric constant. The aims of the current study are to create free volume in the bulk polyamide structure and to reduce the dielectric constant by using β-Ni(OH)2 particles. Method: The composites obtained from β-Ni(OH)2 (flower-like nanoparticles) in a naphthalene-based polyamide matrix were prepared. Firstly, β-Ni(OH)2 nanoparticles were synthesized by microwave-assisted solvothermal technique under various reaction conditions. Then, polyamide/β-Ni(OH)2 composites were prepared via direct dispersion methods at different reinforcement ratios. Results: β-Ni(OH)2 (flower-like nanoparticles) and polyamide/β-Ni(OH)2 composites were prepared successfully. Our studies showed that the dispersion of β-Ni(OH)2 nanoparticles in polyamide matrix is homogenous and prepared composites have good thermal and dielectric properties with promising results for electronic industry. Conclusion: Dielectric properties of the prepared composites decrease with increasing β-Ni(OH)2 nanoparticle content and all composites show low dielectric constant when β-Ni(OH)2 nanoparticle content is over 1 wt.% compared to the pure polyamide.