We present experimental studies on doped and undoped ZnO nanoparticles prepared via cost-effective solution processing techniques towards its applicability for terahertz frequency domain. Scanning electron microscopy (SEM) confirms that the dimensions of synthesised particles spread over 120–275 nm, while x-ray diffraction (XRD) along with energy dispersive x-ray (EDX) characteristics manifests the presence of the desired materials for doped as well as undoped nanoparticles. Further, terahertz-time domain spectroscopy (THz-TDS) data are recorded in transmission mode which are employed to extract several optical parameters (viz. refractive index, conductivity, etc) of the nanoparticulate films spanning the frequency range from 0.2 to 0.9 THz. Doped samples clearly manifest enhanced conductivities because of the presence of metallic components. Cost-effective synthesis of ZnO nanoparticles can be useful for terahertz photonics in future.