Manganese doped alpha-lithium iodate have been synthesized and single crystals have been grown for nonlinear optical applications. The grown crystal has been subjected to single crystal X-ray diffraction to confirm the structure. The crystalline perfection was assessed by high-resolution X- ray diffractometer (HRXRD). Second harmonic generation (SHG) efficiency was found to be 71 times than that of KDP. The UV–Vis-NIR spectroscopic study revealed that the grown crystal has good optical transparency in the visible region clearly indicates that Mn doped α-LiIO3 crystals can be used as window material in optical instruments. Presence of dopant was confirmed by energy-dispersive spectrometry.