Conjunctions That Indicate Cause & Effect

Conclusive coordinating conjunctions (conjunções coordenativas conclusivas), as the name implies, introduce a consequence or conclusion. More specifically, these Portuguese conjunctions indicate a cause and effect relationship between parts of the sentence. The most common are:
por issosoCommunity Slow audio Play audio
portantotherefore, soCommunity Slow audio Play audio Adverb
logoso, thereforeCommunity
For the most part, these can be used interchangeably, with portanto being considered slightly more polished, and appearing more often in professional settings than the others (like ‘therefore’ in English). However, it’s a versatile conjunction that also works in casual contexts (like ‘so’ in English). Examples:
Eu tenho sacos, por isso eu vou de elevadorI have bags, so I will take the elevator (i.e. lift)Community Slow audio Play audio
Não quero ir, portanto não vouI don't want to go, therefore I won't goCommunity Slow audio Play audio
Não estuda, logo não tem boas notasShe doesn't study, so she doesn't have good gradesCommunity Slow audio Play audio
We also have então, which is very similar to logo.
O restaurante fecha ao domingo, então vamos almoçar em casaThe restaurant closes on Sundays, so we’ll have lunch at homeCommunity Slow audio Play audio
Now we’ll move on to por conseguinteconsequentlyCommunity Slow audio Play audio and de modo quesoCommunity , which may be used when you want to sound more sophisticated or professional. Por conseguinte is the more formal of the two, often appearing in academic and literary contexts. It can still be used in a conversation, but it may be a bit too much in familiar, everyday chats.
Já passaram mais de 2 semanas e, por conseguinte, a polícia terminou as buscasMore than two weeks have passed, and thus the police have ended the searchCommunity Slow audio Play audio
Os treinos correram bem, de modo que estou confiante na vitóriaThe training went well, so I'm confident I'll winCommunity Slow audio Play audio
Lastly, we’ll mention pois, which can also be a conclusive conjunction. When used this way, it must come after the verb between commas, like this:
Não vou, pois, poder estar presente na reuniãoI won't, therefore, be able to attend the meetingCommunity Slow audio Play audio
This particular usage is less common and somewhat formal. Rather than directly linking the ideas in the sentence, the positioning of the conjunction signals a subtle reference to whatever had just been said in order to draw a conclusion.