The Retinenes (Retinene₁ and Retinene₂) are chemical derivatives of the dietary supplement vitamin A (see retinol) formed through oxidation reactions. Retinene₁ is better known as retinaldehyde or simply retinal and is fundamental in the transduction of light into visual signals in the photoreceptor level of the retina. Retinene₂, is more formally known as dehydroretinaldehyde.

The energy of impinging photons will convert retinaldehyde from an 11-cis isomer into an all-trans form. In the retina, this conversion induces a conformational change in the surrounding photopsin protein pigment, leading to signaling through the G protein transducin.

Experimentally, it is possible to replace 11-cis retinaldehyde by perfusing retinal tissue preparations with retinaldehyde derivatives. Selective modification of the retinaldehyde structure, particularly the density of electrons in the π-orbitals can lead to insights into the interaction between the retinaldehyde moiety and the surrounding pigment protein.