Recent advances in aluminum-based complexes and their photofunctions

Aluminum, an earth-abundant, inexpensive, and lightweight metal, has recently attracted notable attention as a promising key element in photofunctional materials. Historically, aluminum complexes—most notably tris(8-hydroxyquinolinato)aluminum—were among the earliest compounds explored for device applications. However, subsequent development in optoelectronics lagged behind systems based on boron, transition metals, and lanthanides. Over the past two decades (2005–2025), remarkable progress has been achieved in the molecular design, photophysical properties, and practical applications of aluminum complexes. This review summarizes recent advances in organometallic and coordination materials based on aluminum, beginning with an overview of the structural motifs and coordination environments that define these systems. We then highlight the key properties and emerging functions of aluminum complexes, with particular emphasis on luminescence, thermally activated delayed fluorescence, circularly polarized luminescence, crystallization-induced emission, aggregation-induced emission, and their applications in sensing and photocatalysis.