Аннотация:The role of C2-substituents in the imidazolone ring of borated GFP chromophore derivatives(4-(2-(difluoroboryl)benzylidene)-1H-imidazol-5(4H)-ones) in the degradation process was studied. It wasfound that the nature of this substituent hardly affected their photostability, whereas their sensitivity towardnucleophilic reagents decreased with an increase in size and donating properties of the substituent. Theresults supported an assumption that the introduction of C2 substituents was not a rate-limiting step of thedegradation process of these derivatives and complex C2 substituents were not effective tools for the improvementof their stability.