Based on my experience I would say no. They are both fighting for space on the top 1/3 of the tank and since they similar fish(both able to breathe air) they compete for the same air space as well. If the tank is big enough and you can break up sight lines they might be able to co-exist but even that would depend on the personallities of both fish.
I have to agree. The betta is in the gourami family and for that reason alone putting the two of them togather is not a good idea. This is especially true if the size of the tank is on the small size. They are both territorial fish and given the fact that they are both males will also cause a problem. Better to have one or the other.
i wouldnt mix them. male bettas are pretty aggressive towards other males, and male gouramis have beeen known to be aggressive towards males of other species of goruamis and bettas
I keep a collection of gourami's and all I can say is that they are unpredictable. Some are placid and some are bullies. If you have a few tanks you can experiment and rehouse but otherwise you might want to avoid the situation altogether. A heavily planted tank might give the weaker ones a place to hide but if you get a mean bully he will spend all his time hunting and chasing the weaker ones.