Imidazo-1,5-alkynyl alcohol derivatives were synthesized, and they were cyclized to imidazo-1,4-oxazines by means of cesium carbonate. Propargyl-allene isomerization was examined, and the reaction mechanism was proposed. Moreover, cytotoxicity of synthesized molecules against LN405 cell lines was investigated by means of structure-activity relationship (SAR). With SAR study, toxicities of some functional groups have been shown. In addition, two lead compounds were tested against DNA damaging.