Do we use "pensar que" if we don't have an infinitive?

Question

Hi Inma, I've been enjoying your lessons.Would it be correct to say:"No pienso ir."as:"No pienso que voy a ir."Thanks.

Accepted Answer

Hola Marcos
If the meaning is "I have decided (not) to, I (don't) have the intention to..", which is what we express when using "Pienso + infinitive" or "No pienso + infinitive", then you can't use it as you suggested: No pienso que voy a ir. (incorrect) You need the structure with the infinitive.
When you can use it with "que"  is when expressing opinion, the same we do with no creer que, but be careful to use it with the subjunctive (not the indicative):
No creo que ella sea fea.
No pienso que ella sea fea. 
Saludos
Inma