The development of multifunctional materials, specially nanocomposites, exhibit new and interesting properties which can extend the applicability ranges to diverse fields. In this way, the use of tri metallic nanoparticles, and derives, demonstrated higher efficacy for purification, catalytic activities and as antibacterial agents. This work is concentrated on the fabrication of Fe/La/Zn trimetallic nanoparticles (TNPs) and Fe/La/Zn@GO trimetallic nanocomposite (TNC) using the micro-emulsion method, specially indicated as photocatalysts for remediation of the organic pollutant. An intense characterization was performed by employing techniques as scanning electron microscopy (SEM), X-Ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared spectroscopy (FTIR). The potential applications of the Fe/La/Zn TNPs and Fe/La/Zn@GO TNC were explored for the photodegradation of phenylhydrazine in the presences of sunlight. Furthermore, the photocatalytic studies were performed under different conditions: (a) adsorption (in dark) followed by photocatalysis, and (b) simultaneously adsorptional-photocatalysis straight way in sunlight. It was observed that a reduction of 52% and 57.91% was achieved under sunlight using Fe/La/Zn TNPs and Fe/La/Zn@GO TNC, respectively. The optical band gap of Fe/La/Zn TNPs, and Fe/La/Zn@GO TNCs was found 2.73 eV and 2.30 eV, which lies in semiconductor region. On the other hand, the antimicrobial nature of TNPs and TNC was checked for E. coli and S. aureus. The inhibition zone exhibited a maximum at 150 μg/mL for Fe/La/Zn TNPs (19 mm), and Fe/La/Zn@GO TNC (17 mm). This study revealed that resulting materials can be defined as a novel class of advanced multifunctional materials which can be employed effectively for environmental remediation and antimicrobial studies.