Single crystals of alkali, alkaline earth and transition metal sulphates doped alanine nonlinear optical materials have been grown from solution by slow evaporation method. The isoelectric point of the alanine is 6. So, the growth of crystals has been carried out at pH 6. The various functional groups present in the pure and doped crystals are elucidated from Fourier transform infrared spectroscopy study. UV–Visible transmittance is recorded to study the optical transmittance range for the grown crystals. The grown crystals have been subjected to powder X-ray diffraction studies to identify the crystalline nature. Surface morphology and defects due to dopant were studied by optical microscope. The antimicrobial studies of the grown crystals were studied using two gram positive and two gram negative bacteria.