d="p0010">Two novel pH probes (class="boldFont">L1 and class="boldFont">L2) were facilely synthesized by one-step reaction.
dd><dt class="label">•dt><dd>d="p0015">Fluorescence intensity ratio of class="boldFont">L1 and class="boldFont">L2 can quantify the pH fluctuations.
dd><dt class="label">•dt><dd>d="p0020">class="boldFont">L1 and class="boldFont">L2 show high quantum yield and large two-photon absorption cross-section.
dd><dt class="label">•dt><dd>d="p0025">class="boldFont">L1 and class="boldFont">L2 show excellent selectivity response and remarkable color change to H+.
dd><dt class="label">•dt><dd>d="p0030">class="boldFont">L1 and class="boldFont">L2 were successfully utilized to mapping pH difference intracellularly.
dd>dl>