A new series of photoactivable NADPH mimics bearing one or twoO-carboxymethyl groups on the adenosine moiety have been readily synthesized using click chemistry. These compounds display interesting one- or
two-photon absorption properties. Theirfluorescence emission wavelength and quantumyields () are dependent on the solvent polarity, with a red-shift in a more polar environment (max,em=460-467 nm,> 0.53 in DMSO, and max,em= 475-491 nm,< 0.17 in Tris). These compounds showgood binding affinity towards the constitutive nNOS and eNOS, confirming for thefirst time that thecarboxymethyl group can be used as a surrogate of phosphate. Two-photonfluorescence imaging ofnanotriggers in living cells showed that the presence of one carboxymethyl group (especially on the 3position of the ribose) strongly favors the addressing of nanotriggers to eNOS in the cell context.