A compound, in particular a fluorescent dye, having the structural formula: wherein: each X 1, X 2, X 3, X 4 is independently selected from H, halogen (F, Cl, Br, I), CN, NO 2, OR 1, SR 1, NR 1 R 2, COR 1, COOR 1, CONR 1 R 2, PO 3 R 1 R 2, SO 2 R 1, SO 3 R 1 and R 3, where: R 1 and R 2 can represent H, alkyl, aryl or heteroaryl, and wherein R 1 and R 2 can form together a substituted or unsubstituted 4-7 membered ring; R 3 is alkyl, alkenyl, alkynyl, aryl or cycloalkyl, optionally substituted with one or more heteroatoms independently selected from N, O, S, halogen (F, Cl, Br, I), N 3, amine, OH, OR 1, OCOR 1, aryl, COOR 1, CONR 1 R 2, PO 3 H 2 and SO 3 H, where R 1 and R 2 are defined as above; Y is selected from OR 1, NR 1 R 2, or NR 1 R 3, where R 1, R 2 and R 3 are defined as above; Q is selected from O, S, SO 2, NR, C(R 3) 2, Si(R 3) 2, Ge(R 3) 2, P(=O)R 3, P(=O)OR 3, where R 3 is defined as above, and wherein Q and X 1, taken together with the atoms to which they are bonded, can form a substituted or unsubstituted 5-7 membered ring; L and M are independently selected from OR 1, SR 1, NR 1 R 2 and R 3, where R 1, R 2 and R 3 are defined as above, and wherein L and M, taken together with the atoms to which they are bonded, can form a substituted or unsubstituted 5-7 membered ring; Z is selected from O, S, NR 1, CR 1 R 3 or aryl, where R 1 and R 3 are defined as above, and wherein Z and X 4, taken with the atoms to which they are bonded, can form a substituted or unsubstituted 5-7 membered ring. each X 1, X 2, X 3, X 4 is independently selected from H, halogen (F, Cl, Br, I), CN, NO 2, OR 1, SR 1, NR 1 R 2, COR 1, COOR 1, CONR 1 R 2, PO 3 R 1 R 2, SO 2 R 1, SO 3 R 1 and R 3, where: R 1 and R 2 can represent H, alkyl, aryl or heteroaryl, and wherein R 1 and R 2 can form together a substituted or unsubstituted 4-7 membered ring; R 3 is alkyl, alkenyl, alkynyl, aryl or cycloalkyl, optionally substituted with one or more heteroatoms independently selected from N, O, S, halogen (F, Cl, Br, I), N 3, amine, OH, OR 1, OCOR 1, aryl, COOR 1, CONR 1 R 2, PO 3 H 2 and SO 3 H, where R 1 and R 2 are defined as above; R 1 and R 2 can represent H, alkyl, aryl or heteroaryl, and wherein R 1 and R 2 can form together a substituted or unsubstituted 4-7 membered ring; R 3 is alkyl, alkenyl, alkynyl, aryl or cycloalkyl, optionally substituted with one or more heteroatoms independently selected from N, O, S, halogen (F, Cl, Br, I), N 3, amine, OH, OR 1, OCOR 1, aryl, COOR 1, CONR 1 R 2, PO 3 H 2 and SO 3 H, where R 1 and R 2 are defined as above; Y is selected from OR 1, NR 1 R 2, or NR 1 R 3, where R 1, R 2 and R 3 are defined as above; Q is selected from O, S, SO 2, NR, C(R 3) 2, Si(R 3) 2, Ge(R 3) 2, P(=O)R 3, P(=O)OR 3, where R 3 is defined as above, and wherein Q and X 1, taken together with the atoms to which they are bonded, can form a substituted or unsubstituted 5-7 membered ring; L and M are independently selected from OR 1, SR 1, NR 1 R 2 and R 3, where R 1, R 2 and R 3 are defined as above, and wherein L and M, taken together with the atoms to which they are bonded, can form a substituted or unsubstituted 5-7 membered ring; Z is selected from O, S, NR 1, CR 1 R 3 or aryl, where R 1 and R 3 are defined as above, and wherein Z and X 4, taken with the atoms to which they are bonded, can form a substituted or unsubstituted 5-7 membered ring.