An oxazole-derived Schiff base as a multifunctional fluorescence sensor towards Al3+ and Ga3+ in different media

•A multifunctional fluorescence sensor (G3) was constructed through the introduction of 2, 3-dihydroxybenzylidene.•G3 can be used as a dual sensing platform towards Al3+ and Ga3+ through distinct fluorescence behavior in different media.•The optimized structure, orbital energy and electrostatic potential were calculated to prove the sensing mechanism.•The investigation value of G3 was further conducted through the contrastive study of structural difference.