The present invention provides compounds of formula (I) wherein X and Y represent CH, CH2 or a divalent or trivalent heteroatom under the proviso that X and Y are not simultaneously CH or CH2; m and o represent independently of each other 0 or 1, with the proviso that if m is 0 then the dotted line between Y and the neighboring C atom represents a bond and Y is CH or a trivalent heteroatom, if m is 1 then the dotted line between Y and the neighboring C atom is absent and Y is CH2 or a divalent heteroatom, if o is 0 then the dotted line between X and the neighboring C atom represents a bond and X is CH or a trivalent heteroatom, if o is 1 then the dotted line between X and the neighboring C atom is absent and X is CH2 or a divalent heteroatom; A represents (CH3CR4)p and Q represents (CR9R10)n; n and p represent independently of each other 0 or 1; R6, R7, R13 and R14 denote independently of each other hydrogen, halogen, (C1-4)alkyl, (C1-4)alkylSO2, SO3H, carboxy, (C1-4)alkoxy carbonyl, (C1-4)alkoxy, OH or NR15R16; R1, R2, R3, R4, R9, R10, R11 and R12 denote independently of each other hydrogen, (C1-4)alkyl, carboxy, (C1-4)alkoxy carbonyl or (C1-4)alkoxy, or, when X is CH or CH2 then R1 and R2 can also be OH or NR15R16, or when Y is CH or CH2 then R11, R12 can also be OH or NR15R16; R5, R8, R15 and R16 are independently of each other hydrogen, (C1-4)alkyl, (C1-4)alkoxy, R17O-C(O)-(C1-4)alkyl or (reactive group)-(C1-4)alkyl; and R17 represents hydrogen or (C1-4)alkyl; compositions comprising such compounds, a process for the production of such compounds of formula (I), a method of labeling target structures, especially amyloid plaques, in the brain, a method for identifying Alzheimer's disease, use of a compound of formula I as a near-infrared imaging agent and a conjugate comprising a compound of formula (I) covalently linked to a biomolecule through a reactive group.