The show isn't all that wonderful, however it has several nice songs in it. It did have a very respectable run of 329 performances, though it is widely agreed that that was solely because people wanted to Katharine Hepburn on stage, most especially in a musical.
(There's an apocryphal story -- who knows if it's true -- that when the real Coco Channel, famous designer of clothes and perfume, heard that Hepburn would be portraying her, she was very pleased and excited. But she had thought it would be Audrey, not Katharine. I suspect the story isn't true.)
And here's a treat.
This is a performance from Coco on the 1970 Tony Awards. But what is the special treat is that this video is a remarkable 15 minutes long! Most of it is pure dialogue, leading finally to the song, "Always Mademoiselle." Even by early Tony standards, this is hugely long. My guess is that it was a demand by Katharine Hepburn, something along the lines of "I'll appear on your show, but you must let us showcase the musical and not just give a snippet." I have no particular basis for this guess other than -- a) they never have 15-minute segments, b) Katharine Hepburn famously didn't appear on live TV (it was a major coup when she much later agreed to be interviewed by Dick Cavett, and that came about almost as a whim), c) that just seems to me like something Katharine Hepburn would do, and d) the Tonys would probably have done anything to get Katharine Hepburn to appear.
However it came about, here it is. Katharine Hepburn starring in he musical, Coco