There are many travellers who travel very frequently from Bangkok to Kuala Lumpur for business mainly.
There are many low cost airlines and mainly Malaysian airline and Thai Airways fly on this route if you are looking to travel in business class.
Malaysian airline is using old 737 while Thai is using 777 on this route which is much better than Malaysian airline.
Thai is an only direct option on this route if you want to have good business class experience. Well back on topic that how you can save upto 50% on Thai business class over this route.
Lets look at the thai fares from Bangkok to Kuala Lumpur –
Cheapest Economy class from Bangkok to Kuala Lumpur on Thai – 172 USD one way and 229 USD for round trip.
Cheapest Business class from Bangkok to Kuala Lumpur on Thai – 387 USD One way and 620 USD for roundtrip.
Now lets look at the fares from Kuala Lumpur to Bangkok –
Cheapest Business class from Kuala Lumpur to Bangkok on Thai – 172 USD One way and 298 USD for roundtrip.
I suggest that you should change your point of origin to Kuala Lumpur incase you travel on this route frequently.
You can buy one way ticket from Bangkok to Kuala Lumpur and then always buy round trip from Kuala Lumpur which will easily change your point of origin and you can travel on this route in business class by simply paying economy class price.
Business class ticket from Kuala Lumpur is valid for 12 months and you can change the date of travel for free.
It is difficult for some travel agent to issue those ticket on given price in Thailand but there are some travel agents who can help or you can simply buy them on Thai airways website.