In the present study, Pure and Eu doped ZnSO4·7H2O single crystals were grown using slow evaporation and seed hanging methods respectively. The structural and optical properties of the grown crystals were studied using various techniques. X-ray diffraction studies (XRD) confirmed that the crystal belongs to the orthorhombic crystal system with space group P212121, UV–visible spectroscopy (UV–Vis) studies revealed that the shift of absorption peak towards the lower wavelength makes the crystal applicable for SHG, NLO, and Optical applications. Using Fourier transform Infrared spectroscopy (FTIR), the FTIR spectrum of the crystals was analyzed and found the peaks at 3159 cm−1, 1655 cm−1, 1057 cm−1 which represent the OH group, HO-H vibration, and sulfoxide bond respectively. The existence of Europium in the crystal is authenticated by Energy Dispersive Analysis of X-rays (EDAX), and the surface morphology is reported using Scanning Electron Microscope (SEM) technique. An analysis of photoluminescent (PL) spectrum validated that, with the excitation wavelength of 320 nm a broad peak at 639 nm was observed in the emission spectrum and the transitions from 5D0 to 7FJ (where J = 1,2&4) levels in the emission spectrum represent the Europium (Eu) ion transitions with orange-red emission. The Antimicrobial nature of the pure and Eu doped crystals was studied for two gram-positive bacteria (Staphylococcus aureus, Enterococcus Faecalis), two gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae), and two fungi (Candida, Aspergillus). For the higher concentration of the Eu doped ZnSO4·7H2O, the zone of inhibition observed was 18,17.5,16.5,16.5 mm for E. coli, Klebsiella pneumoniae, Staphylococcus aureus, Enterococcus Faecalis, and 17, 18.5 mm for Candida, Aspergillus respectively. From the antimicrobial studies, it was evident that the crystal can also act as a good antimicrobial agent as the zone of inhibition was increased with the increase in the concentration of the testing material.