heteroconjugation

  1. [obsolete]Association between a base and the conjugate acid of a different base through a hydrogen bond (B' ... HB+ or A'H ... A). The term has its origin in the conjugate acid–base pair and is in no way related to conjugation of orbitals Heteroassociation is a more appropriate term.
  2. [obsolete] Some authors refer to conjugated systems containing a heteroatom, e.g. pyridine, as 'heteroconjugated systems'. This usage is discouraged since it inappropriately suggests an analogy to homoconjugation, and conflicts with the currently accepted definition of that term.
Source:
PAC, 1994, 66, 1077 (Glossary of terms used in physical organic chemistry (IUPAC Recommendations 1994)) on page 1120