I have the string "open this and close that" and I want to obtain "open this and" and "close that". This is my best attempt:

>>>print( re.split(r'[ ](?=(open|close)+)', "open this and close that") )
['open this and', 'close', 'close that']

I'm using Python 3.4.

Split string with multiple delimiters in Python replaces the triggers. I need them, the script has to know if I want to turn off or on a light, and not only which light is.

You can simply use the grouping if you know what letter are you using.

import re
line = re.sub(r"(open this and) (close that)", r"\1\t\2", "open this and close that")
print (line)