Photoinitiating systems based on BF2 derivatives and tetramethylammonium phenyltriethylborate salt were tested in photopolymerization reactions through the photo-DSC method. The good rates of TMPTA polymerization and final monomer conversion were obtained for tested system. The effect of the type of heterocycle on their properties was revealed. The excited state processes, investigated by nanosecond flash photolysis, lie on a fast excited state photoinitiated cleavage leading to reactive species. A triplet state is observed for investigated derivatives.