In recent years, some X-ray structural and computational evidence has emerged for noncovalent carbon bonding (C-bond). However, evidence of C-bonds in solution is limited. Herein, from the conformational analyses of strategically designedN-methyl-N,N'-diacylhydrazines, we for the first time show that C-bonds can be modulated to control the conformational preferences of small molecules in solution. We show that unusual N(amide)?C-X noncovalent carbon bonding interactions stabilize thetrans-cis(t-c) amide bond rotamers ofN-methyl-N,N'-diacylhydrazines over the expectedtrans-trans(t-t) rotamers. © The Royal Society of Chemistry 2020.