Open innovation has been widely discussed ever since P&G publicly pronounced that "Open innovation is a way for companies to avoid the stale, repetitive thinking that can happen when employees are accustomed to their internal ways of solving problems". The goal of open innovation is to connect innovation problem to the best existing technical solution to this problem that can be found outside of company's R&D. The general concept of open innovation has been widely accepted and practiced. However, in practice, open innovation frequently works inefficiently because problem at the input is not formulated properly or is a wrong problem to be solved. The objective of this article is to discuss this challenge of open innovation and demonstrate - through the prism of chemical engineering - how one of the main TRIZ tools, functional approach, can increase the effectiveness of open innovation. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.