The development of photodynamic therapy (PDT) has significantly advanced cancer treatment. While metal complex-based photosensitizers exhibit high photosensitivity, their metal centers may be susceptible to nucleophilic attacks, potentially leading to reduced sensitizing performance. In contrast, metal-free photosensitizers can face limitations in biological environments, often associated with aggregation-induced deactivation of excited states. To address these challenges, we synthesized two novel β-hydroxyimine boron complex-based photosensitizers, TPE-SF and TPE-2SF, which exhibit aggregation-induced emission (AIE) characteristics and promising antitumor performance in cellular and in vivo models. Theoretical calculations reveal that the intramolecular donor-acceptor (D-A) structure contributes to a reduced singlet-triplet energy gap (ΔE_ST) and enhanced the spin-orbit coupling (SOC) matrix element, thereby facilitating intersystem crossing (ISC) and supporting their photosensitizing properties. Overall, this work provides insights into the design of metal-free and heavy-atom-free photosensitizers and highlights the potential of β-hydroxyimine boron complexes for photodynamic therapy.