The construction of C-N bonds is of great importance in the fields of biology, medicine, chemistry and materials science. Here, the replacement of organic base from pyridine to piperidine in the Knoevenagel condensation process unexpectedly yields a series of novel organic molecules containing C-N bonds. Interestingly, the synthesis method does not require any external transition-metals catalysis, and photo-/electro-catalysis. Additionally, when the new compound 1bis added as a third component to a well-known binary system of PM6:Y6, the efficiency of the organic solar cell is significantly improved, resulting in an outstanding efficiency of 18.0%, which is one of the highest values reported to date for PM6:Y6-based ternary organic solar cells.