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Although second near-infrared (NIR-II, 1000-1500 nm) light has attracted considerable attention, especially for life sciences applications, the development of organic dyes with NIR-II absorption remains a formidable challenge. Herein we report the design, synthesis, and electronic properties of 20π-electron antiaromatic benziphthalocyanines (BPcs) that exhibit intense absorption bands in the NIR region. The strong, low-energy absorption of the antiaromatic BPcs is attributed to electric-dipole-allowed HOMO-LUMO transitions with narrow band gaps, enabled by the reduced structural symmetry of BPc compared with regular porphyrins and phthalocyanines. The combination of peripheral substituents and a central metal decreases the HOMO-LUMO energy gaps, leading to the extension of the absorption bands into the NIR-II region (reaching 1100 nm) under reductive conditions., (© 2024 The Authors. Chemistry - A European Journal published by Wiley-VCH GmbH.)

Despite possessing higher tissue transmittance and maximum permissible exposure power density for skin relative to other electromagnetic waves, second near-infrared light (1000-1350 nm) is scarcely applicable to subcutaneous photoelectric conversion, owing to the companion photothermal effect. Here, skin thermal management is conceived to utmostly utilize the photothermal effect of a photovoltaic cell, which not only improves the photoelectric conversion efficiency but also eliminates skin hyperthermia. In vivo, the output power can be higher than 500 mW with a photoelectric conversion efficiency of 9.4%. This output power is promising to recharge all the clinically applied implantable devices via wireless power transmission, that is, clinical pacemakers (6-200 µW), drug pumps (0.5-2 mW), cochlear (5-40 mW), and wireless endo-photo cameras (≈100 mW)., (© 2023 Wiley-VCH GmbH.)