Nitricoxidehasplayedanimportantroleinmanyphysiologicalandpathologicalprocessesasakindofimportantgassignalmolecules.Inthiswork,anewfluorescentprobeLysoNO-NaphfordetectingNOinlysosomesbasedon1,8-naphthalimidewasreported.LysoNO-Naphhassub-groupsofo-phenylenediamineasaNOreactionsiteand4-(2-aminoethyl)-morpholineasalysosome-targetablegroup.Thisprobeexhibitedgoodselectivityandhighsensitivity(4.57mmol/L)towardNOinawidepHrangefrom4to12.Furthermore,LysoNO-NaphcanbeusedforimagingNOinlysosomesinlivingcells.