Fluorescent Isoindoline Dyes

A compound of the following formula:

• wherein Y1 and Y3 are independently S, O, or NR1 and S, O, or NR3, respectively, with at least one of Y1 and Y3 being NR1 and NR3, respectively, R1 and R3 each being an atom or a functional group, wherein R1 and R3 can optionally form a ring;
• and X1, X2, and X3 are independently N or CR4, N or CR5, and N or CR6, respectively, R4, R5, and R6 each being an atom or a functional group, wherein R4 and R5 and/or R5 and R6 can optionally form a ring or R4 and R6 can optionally form a ring;
• wherein R1 and R3 are independently selected from the group consisting of H, a halogen, a hydroxy group, an amino group, a carboxyl group, an aliphatic group, a heteroaliphatic group, a cyclic group, a heterocyclic group, an aromatic group, a heteroaromatic group, and a combination thereof;
• wherein R, is selected from the group consisting of:
• wherein X=S, O, NR;
• R=an alkyl group or H;
• and, n can be any number of CH2 groups.