Ovarian cancer is a global problem, and is typically diagnosed in the middle or late stages, with a mysterious abdominal mass or atypical abdominal metastases due to the lack of specific initial diagnostic methods. Dual-modal near-infrared II (NIR-II, 1,000–1,700 nm) fluorescence/photoacoustic imaging has great potential in early ovarian cancer diagnosis and image-guided surgery due to its high sensitivity and deep penetration. Herein, we report a novel organic NIR-II dye (H10) with excellent aggregation-induced-emission (AIE) characteristics (I/I₀ > 1.6) utilizing a selenadiazolo-[3,4-f]benzo[c][1,2,5]thiadiazole (ST)-based building block. Then, water-soluble and biocompatible H10@follicle-stimulating hormone (H10@FSH) dots with superior optical/photoacoustic properties and a tenfold increase in ovarian-specific targeting ability were synthesized. Finally, for the first time, in vivo dual-mode NIR-II fluorescent/photoacoustic (PA) imaging and image-guided surgery of patient-derived tumor xenograft (PDTX) and micro-metastatic abdominal ovarian cancer lesions were investigated. This novel strategy will establish a new method for early detection of ovarian cancer and significantly improve the prognosis of ovarian cancer patients.