Provided herein are compounds and compositions which comprise the formulae as disclosed herein, wherein the compound is an amyloid binding compound. An amyloid binding compound according to the invention may be administered to a patient in amounts suitable for in vivo imaging of amyloid deposits, and distinguish between neurological tissue with amyloid deposits and normal neurological tissue. Amyloid probes of the invention may be used to detect and quantitate amyloid deposits in diseases including, for example, Down's syndrome, familial Alzheimer's Disease. In another embodiment, the compounds may be used in the treatment or prophylaxis of neurodegenerative disorders. Also provided herein are methods of allowing the compound to distribute into the brain tissue, and imaging the brain tissue, wherein an increase in binding of the compound to the brain tissue compared to a normal control level of binding indicates that the mammal is suffering from or is at risk of developing a neurodegenerative disease.