Di-4-ANEPPS is considered a old standard of optical mapping membrane potentials. However, its short wavelength, higher internalization rate and small fluorescence change limit its use in some biological samples. Di-4-ANBDQPD and Di-4-ANBDQBS demonstrated 50-100% _F/F signal enhancement than di-4-ANEPPS in Tyrode perfused ventricular wall preparations.