"Eso es un coche."

I didn't know either, but apparently, "eso" is used by itself, as in "This is a car," whereas "ese" is more like an adjective, used before a noun as in "This white building."

I think it's because when it's an adjectiv (like in "Ese edificio") there is no neutral form, only ese/esa/esos/esas.

I would say (but I'm not native english speaker) that you could see the difference as: - "This [pronoun for car] is a car" -> "Ése es un coche". Because this stand for a masculine word. - "This [pronoun for an indeterminate thing] is a car" -> "Eso es un coche".

NB : When it's a pronoun, you can find it with an accent mark on the first "e" : ése/ésa/ésos/ésas (at least up to 2010, after the RAE made some change and you should - at least in Spain - put an accent mark but many still do it). And, as a neutral pronoun, "eso" (never with an accent mark) exists only at singular.