The software is a set of tools dedicated to the construction of complex carbon nanotube structures for use in computational chemistry. CoNTub 1.0 was the first implementation for building these complex structures and included nanotube heterojunctions, while CoNTub 2.0 is mainly devoted to three-nanotube junctions. Its aim is to help in the design and research about new nanotube-based devices. CoNTub is based on the strip algebra, and is able to find the unique structure for connecting two specific and arbitrary carbon nanotubes and many of the possible three-tube junctions.