​Synthesized nanocomposite of protonated polyaniline with camphorsulfonic acid (PANI‐CSA) hosted in poly(methyl methacrylate) (PMMA) and incorporated with nickel nanoparticles (NiNPs) were coated as thin films on activated fused silica substrates using oxygen‐plasma and spin coating techniques. Weight percent ratios of 0, 10, 20, 30, 60, and 90% of NiNPs with respect to PANI‐CSA thin films have been studied in order to investigate the optical, structural, and morphological properties of (PANI‐CSA‐PMMA)/NiNPs by employing UV–Vis spectrometer, XRD, scanning electron microscopy (SEM), contact angle (CA) goniometry, impedance analyzer, and thermogravimetric analysis. Deduced refractive indices (n) from UV–Vis data were in the range from 1.5 up to 2.2. SEM micrographs show the typical crystalline structure of PANI was vanishing gradually with increasing the NiNPs content. Optical properties such …​