Can i make operation in bit level by using C#?
I want to implement DES Cipher in CBC mode.

Should be possible, depends exactly what you want to do but I've
done bitwise ops for implementing security algorithms.

Sample code below:

static public int OneByteValToByteStream(ref byte[] byteArr, int nStartIndex, byte byteVal)
{
    for(int i=0; i<1; i++)
        byteArr[nStartIndex++] = (byte)((byteVal>>(i*8))&0x00FF);
    return nStartIndex;
}

    for (j=0; j<2; j++)
    {
      x0 >>=1; if (x1 & 0x1) x0 |= 0x80;
      x1 >>=1; if (x2 & 0x1) x1 |= 0x80;
      x2 >>=1; if (x3 & 0x1) x2 |= 0x80;
      x3 >>=1; if (x4 & 0x1) x3 |= 0x80;
      x4 >>=1; if (carry & 1) x4 |= 0x80;

      carry >>=1;
    }