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Two‐/multi‐photon excited luminescence (TPEL/MPEL) in metal‐organic frameworks (MOFs) underscores the tunable optical properties of MOFs, which can be achieved through intrinsic structural design, guest molecule incorporation, and post‐modification techniques. As a nonlinear optical upconversion process enabled by photon interactions, TPEL/MPEL highlights promising applications in bioimaging, anti‐counterfeiting, and other advanced fields. This review by Wang et al . systematically explores the underlying mechanisms, synthesis strategies, and emerging technological prospects in this domain. More details are discussed in the article on pages 717—735. image