MATCH (o:Organization)-[profile:ORG_ADMIN]-(u:User) WHERE toLower(u.firstName) CONTAINS toLower('a') RETURN u This fails telling me Expected a string value for toLower , but got: StringArray[Nechemia, Mendi, Shainy, Chana, Yosef Y., Chanie, Menachem, Aaron, Levi, Menachem Mendel]; consider converting it to a string with toString(). However, this runs without any issue: MATCH (u:User) WHERE toLower(u.firstName) CONTAINS toLower('a') RETURN u