It's called "The Old Benoni" Defense. Look it up.
is c5 a valid response to d4?

The percentages (44/25/29) are terrible for black. I've tried it with zero success except in blitz. Have you tried the French Defense?

I just looked at the French defense and I do like the looks of it, but I suppose that i was just looking for a way that black could force itself into a sicilian position. Although like you said, aquiredtaste, the percentages aren't good for the old benoni defense.
Before I was playing dutch stonewall against d4 and I haven't had much success for the few times that I tried it.

I would recommend the Modern Benoni before playing the Old Benoni. I played it for some time, but found that it was difficult to generate counterplay.

Why does moving the knight out first, create better play in the Modern Benoni vs. not moving the knight first in the Old Benoni?

White is forced to show his hand in the Modern Benoni. The Old benoni allows white to gain a solid positional advantage.

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I think it might be good against lower rated players because they won't want to go d5, but that begs the question, should we play our "A" game against everyone ? (I don't include internet chess in this consideration). I believe we should play our best game and if it takes longer to beat a lower rated player , so be it...
..yes I think some players will be too timid to play 2d5 against 1d4 c5....
(From a chess philopshy point of view I believe that white's option to play d5 at some point in many 1d4 opening variations is what makes 1d4 superior to 1e4 because with the Sicilian black will always be able to chop off whites central pawn for a less central pawn. I would rather have the white side of a Kings Indian with the d5 pawn phalanx than have to play against the Maroczy Bind )

You would be able to develop the queen easily, but as you will see--white will have a better time with central control.
I was just wondering if this line has any potential whatsoever against d4. It sort of presents an unexpected move, and forces white to move its pawn away from the center, and white has to work too hard to support it if it wants to keep the pawn. From there it allows black to go into standard sicilian play if they so choose. (which is what I am hoping for at least)
So is this a move that will just work against lower rated players or it is overall sound? I'm sure that there has to be some line somewhere that an experienced/skilled can utilize to crush this, but I haven't seen it yet. I've only tried this move in one live game so far, and the game turned awfully sloppy, so I'm not sure that its best example of what I'm hoping for.
So are there any thoughts or words of wisdom that anyone can provide?
Right now, the only openings that I am comfortable with for black are sicilian ones, so I am kind of looking for a way to force it to happen more or less.
Thanks!