In this study, we fabricated an economical, non-toxic, and convenient magnetic nanocomposite of CuFe2O4 nanoparticles (NPs)/carbon quantum dots (CQDs) of citric acid via the co-precipitation method. Afterward, obtained magnetic nanocomposite was used as a nanocatalyst to reduce the ortho-nitroaniline (o-NA) and para-nitroaniline (p-NA) using a reducer agent of sodium borohydride (NaBH4). To investigate the functional groups, crystallite, structure, morphology, and nanoparticle size of the prepared nanocomposite, FT-IR, XRD, TEM, BET, and SEM were employed. The catalytic performance of the nanocatalyst was experimentally evaluated based on the ultraviolet–visible absorbance to assess the reduction of o-NA and p-NA. The acquired outcomes illustrated that the prepared heterogeneous catalyst significantly enhanced the reduction of o-NA and p-NA substrates. The analysis of the absorption showed a remarkable decrease for ortho-NA and para-NA at λmax = 415 nm in 27 s and λmax = 380 nm in 8 s, respectively. The constant rate (kapp) of ortho-NA and para-NA at the stated λmax was 8.39 × 10–2 s−1 and 5.48 × 10–1 s−1. The most highlighted result of this work was that the CuFe2O4@CQD nanocomposite fabricated from citric acid performed better than absolute CuFe2O4 NPs, since nanocomposite containing CQDs had a more significant impact than copper ferrite NPs.