Early-stage ovarian cancer is typically asymptomatic. Despite successful initial treatments, 80–90% of women with advanced cancer experience tumor recurrence. For real-time ovarian cancer surgeries, we have identified an optimized pH-sensitive near-infrared fluorogenic dye (CypH-11) which remains non-fluorescent in normal tissues but becomes fluorescent immediately upon contact with cancer tissue of which microenvironment is slightly acidic. We hypothesize the cancer selective staining by CypH-11 will enhance the precision and efficacy of surgical debulking procedure. This targeted approach aims to identify small and occult lesions that may otherwise go unnoticed, ultimately leading to a more favorable surgical outcome. This figure illustrates a case where CypH-11 was sprayed onto the exposed abdomen and imaged at 5 min. The CypH-11 signal overlaps well with the GFP positive SKOV3 tumor.