Learn French: Voici les cinq finalistes, dont deux ont un croquis intéressant ! - Here are the five finalists, two of whom have an interesting sketch!

In this lesson's context, dont introduces a subset of a group. It translates to "of whom" or "of which." When paired with a number or quantity (like deux, plusieurs, or la plupart), you place dont first, followed by the quantity, and then the verb: dont deux ont... (of whom two have...).

Could I use desquels instead of dont in this sentence?

You might be tempted to say desquels deux ont... because desquels means "of which/whom," but this is incorrect in French. To pull a numerical subset out of a previously mentioned noun (like the finalists), dont is the standard relative pronoun to use.

Why is croquis singular if two people have one? Shouldn't it be des croquis intéressants?

French often keeps the object singular if each person in the subject group possesses exactly one of that item. Using the singular un croquis clearly expresses that each of the two finalists has one sketch. If you used the plural, it could imply that they each submitted multiple sketches.

Is croquis just another word for dessin?

They are related but distinct! A croquis specifically means a "sketch" or rough draft, usually drawn quickly to capture an initial concept (very common in fashion or architecture). A dessin is the general word for "drawing" and can be a completely finished piece.