Molecular engineering has emerged as a highly interdisciplinary field of study on function-directed molecular design,material synthesis,and property optimization,accompanied by a deep understanding of the structure-property relationship.In this review,our recent progress on the design and preparations of photofunctional metal complexes and related materials is summarized from the perspective of coordination molecular engineering.In particular,a series of cyclometalated diruthenium complexes with near-infrared (NIR) electrochromic property have been synthesized by engineering the bridging ligand structures.A group of ruthenium-amine conjugated complexes with multistage NIR electrochromism are obtained on the basis of a multicenter strategy.By engineering the ligand structures,a series of new ruthenium and platinum complexes are synthesized to show switchable luminescence in response to various stimuli.In addition,photoluminescent ruthenium,iridium,and platinum complexes are assembled to afford micro/nanocrystals with well-defined morphology and luminescent properties.