Disclosed are novel crystalline polymorphic forms of 4-(4-(imidazo[1,2-b]pyridazin-2-ylmethoxy)phenyl)-2,2-dimethyl-5-(pyridin-4-yl)furan-3(2H)-one and salts thereof, methods of preparing the crystalline polymorphic forms and salts thereof, pharmaceutical compositions comprising the crystalline polymorphic forms and salts thereof, and methods of treating CNS disorders, eating disorders, obesity, compulsive gambling, sexual disorders, narcolepsy, sleep disorders, diabetes, metabolic syndrome, schizophrenia, schizo-affective conditions, Huntington's disease, bipolar disorders, dystonic conditions and tardive dyskinesia, or for use in smoking cessation treatment in a patient using the crystalline polymorphic forms and salts thereof.