A) The highest photoacoustic signal among the small molecule dyes tested was observed for IRDyeQC-1, ATTO 740, RD831 and ICG. B) Among the dyes that provided a high photoacoustic signal, ATTO-740 showed superior photostability not changing the appearance after being exposed to light for 7 days. C) The absorbance of ATTO740 did not change during a 30 minute irradiation with 740 nm laser light. D) GRPR agent, AA3G-740 consists of antagonist binding moiety, triple glycine linker and ATTO740 as a signaling dye. The control agent, CAA3G-740, has the same signaling dye and linker but a scrambled binding sequence. E) AA3G-740 provides the highest photoacoustic signal at 750 nm and highest fluorescence at 760 nm.