They are not but are related both are not in the Betta family they are in the antoibide. Which Betta is in.
Actually betta and the common aquarium gourami are from the family Osphronemidae. Anabantidae is the climbing perches but does include some aquarium fish like the African leaf fish (Ctenopoma acutirostre). Both of these families are part of the suborder Anabantoidei also known as the labyrinth fishes. Taxonomy can be confusing.