Poi vs Dopo
Are they synonyms or do they mean different things and have different rules of usage?
"Then" and "after / later on" correspond to poi and dopo, respectively.
The main difference is that dopo can act both as an adverb and as a preposition:
Dopo siamo usciti. = Later on we went out. [adverb]
Mangeremo dopo. = We'l eat later on. [adverb]
Dopo quell'incrocio la biblioteca è il primo edificio a sinistra. = After that crossing, the library is the first building on the left. [preposition]
C'è qualcun altro dopo di te. = There is someone else after you. [preposition]
Note that using the preposition dopo before a personal pronoun (e.g. te) the further preposition di must be added.
Instead poi can only act as an adverb, and it is usually spoken only at the beginning of the clause/sentence:
Poi siamo usciti. = Then we went out.
Abbiamo mangiato, poi abbiamo guardato la TV. = We ate, then we watched the TV.
In some cases it can mean "also", "moreover", "furthermore":
- Non mi interessa il corso di francese, poi è anche piuttosto caro. = I'm not interested in the French course, it is also quite expensive.
There are some exceptions as to the position of poi, such as when it is used in the expression prima o poi ("sooner or later"), which can be spoken at either end of the sentence:
- Riuscirai a superare l'esame, prima o poi. = You'll manage to pass the exam, sooner or later.
In a few cases poi can replace dopo, taking the same meaning of "later on":
- Adesso lavoriamo, mangeremo dopo. / poi. = Now let's work, we'll eat later on.
Using poi with this meaning places more emphasis than dopo on "later on".