Fluorescent probes for biological studies

A compound of formula (I):

• where R4, R5, R6, R7, R8, and R9 are each independently hydrogen, fluorine, or alkyl, where one of R6 or R7 is —NR1R2;
• R1 and R2 are each independently hydrogen or alkyl;
• or
• R1 and R2 together with the nitrogen to which they are attached, may form a substituted or unsubstituted 5- or 6-membered ring;
• wherein said nitrogen is not conjugated with said 5- or 6-membered ring;
• R3 is hydrogen or a N-protecting group;
• n is 1, 2, 3 or 4.