Although のに is often thought of as a simple combination of the particles の and に, it is actually its own particle, with the meaning of ‘despite’, or ‘in order to’. In this lesson, we will focus primarily on the ‘despite’ nuance.
Due to のに being a 接続助詞（せつぞくじょし） (conjunction particle), it can be linked to almost any word type, to show that ‘despite (A), (B)’. As with many conjunction particles, な will be required after a noun/な-Adjective, but before のに.

• 明日（あした）テストがあるのに彼（かれ）は勉強（べんきょう）をしないでゲームをしている。
  Despite having a test tomorrow, he is playing games without studying.
• 何（なん）で納豆（なっとう）は臭（くさ）いのに美味（おい）しいの？
  Why does natto taste good, despite smelling bad?
• 彼（かれ）はイケメンなのにいつも汗臭（あせくさ）い。
  Even though he is a good looking guy, he always smells like sweat.
• この車（くるま）はスポーツカーなのに遅（おそ）い。
  Despite being a sports car, this car is slow.

It is also possible to see だのに, instead of なのに, but this is something that is only seen in certain dialects, and would be considered incorrect by the vast majority of native speakers.

• 虫歯（むしば）だのに、チョコレートを食（た）べたから歯（は）が痛（いた）い。
  My tooth hurts because I ate chocolate, despite having a cavity.