The invention is in general directed to compounds and methods for diagnosing, preventing or alleviating the symptoms of amyloid-associated diseases, for example, neuronal diseases, such as, for example, Alzheimer's disease, methods of screening for compounds useful in preventing or alleviating the symptoms of amyloid-associated diseases, methods of diagnostic imaging of A-beta fibrils, and compounds and methods useful for studying normal or disease-associated cellular mechanisms relating to amyloid proteins.