Mono phase LiNb3O8 (LN), a compound that comes during the processing of LiNbO3 is synthesized as thin films using sol gel process followed by microwave annealing. Initial studies like phase determination, structure and microstructure of this particular compound are done. XRD pattern confirmed LN as monoclinic with no preferred orientation. From Raman spectroscopy, we found that crystallization is not uniform and new peaks are appearing. Untraceable phases have been identified from Raman imaging. The broadening of peak width is increasing with increase in temperature. Low frequency modes are due to the Li deficiency sites occupied by Nb ions and higher frequency peaks are due to oxygen displacement. Non stoichiometric phases can be identified from color contrast in Raman imaging. Microwave annealing is a successful method to obtain LiNb3O8 thin films.