Characters' actions are important in pretty much any play, and The Chairs is no exception. The Old Man and Woman spend most of their days hanging out in their house playing pretend. This lack of significant action highlights the boredom and meaninglessness of their lives. As we watch them scurry about the house, waiting for their invisible guests, we learn just how important this gathering is to both of them. Both hope that the delivery of the message will bring meaning to their lives. When they commit suicide at the end, we realize just how important the message is to them. Now that the message is about to be delivered, they feel their lives are complete. Too bad it doesn't actually happen.
The Old Man continually reminds us that he is a general factotum, meaning he does a little bit of everything around the house. The fact that he doesn't have any one particular occupation shows how he's gone through life without committing himself to much of anything. Perhaps he's just been too afraid to try. His wife is constantly reminding him of his wasted potential. Of course, there is the great message, which he has apparently been working on his whole life. Notice, though, that he's afraid to deliver it himself and has hired the Orator to do it for him. The fact that the Old Man is a general factotum also makes him a bit of an everyman. Perhaps, the Old Man's wasted life is meant to represent the ultimate meaninglessness of all of our existences.
It seems significant that the Old Man doesn't have a name. He is anonymous, which highlights his status as an everyman. Rather than being a singular, fully-fleshed-out character, he could be seen as representing all of humanity. His meaningless, wasted life could represent the supposed meaninglessness of all our lives.
The Old Woman, on the other hand, does seem to have a name – Semiramis. This in an allusion to a legendary Assyrian queen who was famous for having her lovers killed after she slept with them. Ionesco's choice of this name for the Old Woman could be interpreted in any number of ways. When we see her getting frisky with the invisible Photo-engraver, we see that she definitely has a potentially destructive sexual side to her, much like the legendary queen.
Also, the name Semiramis suggests the rise and fall of civilizations. Legend tells us that Semiramis was once a great warrior queen; now, of course, her empire is no more. This resembles the way in which the Old Man and Woman's society has crumbled. Their beloved city of Paris is now just a distant memory, reminding us that everything that humanity builds will one day disappear.