Imaging agents of formulas (I)-(V) and methods for detecting neurological disorders comprising administering to a patient in need compounds of formulas (I)-(V) capable of binding to tau proteins and &bgr-amyloid peptides are presented herein. The invention also relates to methods of imaging A&bgr and tau aggregates comprising introducing a detectable quantity of pharmaceutical formulation comprising a radiolabeled compound of formulas (I)-(V) and detecting the labeled compound associated with amyloid deposits and/or tau proteins in a patient. These methods and compositions enable preclinical diagnosis and monitoring progression of AD and other neurological disorders.