What to play against the Catalan

I play the Catalan as white and the Nimzo as black, which means I have to face my favourite white opening with the black pieces. The trouble is that with most lines of the Open Catalan after a few moves of theory black is in an endgame with few winning chances, while the closed setups don't seem terribly interesting to me as I don't really like Queen's Indian style positions. I don't have the liberty of playing the Modern Benoni as I play the Ragozin which can transpose to the Catalan avoiding the Benoni line. What should I play?

Your theoretical description looks too general. Post, at least, 1 diagram. 

The first thing I wonder is whether you really like the catalan, because none of the lines you propose look very threatening for black, One of the recent books on the Ragozin by IM Pert proposes 5...Bb4ch 6Bd2  Bd6. You can look for posts by IM Pfren who likes this opening. 

Another recent book on gueens gambit declined proposes 4...dxc4 5Bg2 a6 which looks complicated. 

Personally don;t see much wrong with the straightforward 4...Be7 line, black may be a pawn down, but in the opposite coloured bishop position, white is the one having to be careful with his king.

If you want to play the ...Nc6 Open Catalan line, then the right move order is 5...a6 first (no 6.Qa4).

I think the Dutch Defense is a good option against the Catalan as is the KID.

Thanks pfren, I think I will go for this

So the OP is away happy everything explained. Meanwhile after 5...a6 the game can continue with 6Ne5 or 60.0 with potentially more problems to solve than any of the other lines the OP didn't like. Nitrlis might cover everything nicely in his Queen's Gambit book. Haven't really gone into because the lines very complex , don't seem consistent to me with the straightforward approach of the rest of the book. 

Not long ago Thrillerfan showed a game of his with 6a4, were an opponent of his, in I expect not untypical  case,  didn't understand what he was trying to do, and lost horribly.