Are Thunbergia and Melicytus in the same family?
no
Thunbergia
Thunbergia is a genus of flowering plants in the family Acanthaceae, native to tropical regions of Africa, Madagascar and southern Asia.
 "Thunbergia" species are vigorous annual or perennial vines and shrubs growing to 2-8 m tall.
 The generic name honours Carl Peter Thunberg.
Melicytus
Melicytus is a genus of flowering plants in the family Violaceae.
 "Hymenanthera" is a synonym.
Melicytus crassifolius
Melicytus crassifolius (thick-leaved mahoe; syn.
 "Hymenanthera crassifolia" Hook.f.)
 is an ornamental plant of Violaceae family, which is native to New Zealand. Melicytus novae-zelandiae subsp. centurionis
Melicytus novae-zelandiae " subsp. "
 centurionis is a flowering plant in the violet family.
 It is a subspecies of "Melicytus novae-zelandiae", known in New Zealand as Coastal Mahoe.
 The subspecific epithet honours the military Captain James Doran McComish (1881–1948), who made several visits in the 1930s to collect plants on Lord Howe Island. Melicytus ramiflorus
Melicytus ramiflorus (māhoe or whiteywood) is a small tree of the family Violaceae endemic to New Zealand. Thunbergia mysorensis
Thunbergia mysorensis, also called Mysore trumpetvine or Indian clock vine, is a species of flowering plant in the family Acanthaceae.
 A woody-stemmed evergreen, this vine is cultivated in Spain (south) and native to southern tropical India.
 The specific epithet "mysorensis" is derived from the city of Mysore.
 Other vernacular names include brick & butter vine, lady's slipper vine, and dolls' shoes due to the flower shape and large size. Melicytus angustifolius
Melicytus angustifolius is a plant species in the family Violaceae.
 It is endemic to New Zealand. Melicytus lanceolatus
Melicytus lanceolatus, commonly called Narrow-leaved māhoe or māhoe-wao, is a small tree of the family Violaceae endemic to New Zealand. Thunbergia grandiflora
Thunbergia grandiflora is an evergreen vine in the family Acanthaceae.
 It is native to China, India, Nepal, Indochina and Burma and widely naturalised elsewhere.
 Common names include Bengal clockvine, Bengal trumpet, blue skyflower, blue thunbergia, blue trumpetvine, clockvine, skyflower and skyvine. Thunbergia gregorii
Thunbergia gregorii, commonly known as orange clockvine or orange trumpet vine, is a herbaceous perennial climbing plant species in the family Acanthaceae, native to East Africa and sometimes cultivated as an ornamental vine.
 The bright, pure all-orange flowers distinguish it from the related black-eyed Susan ("Thunbergia alata").