Should i take my two year old to the doc if he has yellowish green snot? no fever, and he has been sleeping through the night, occasional dry cough

Cough: The most common diagnosis, given the symptoms you describe, is a viral illness. These often make a child uncomfortable, but are ultimately harmless. However, if the symptoms persist for more than a few days, even if he is comfortable, it's worth a look by your doctor. Additionally, if anything else changes (ie: fever, decreased appetite, irritability, unable to sleep at night), have him checked.