Presented review paper is mainly focused on photoinitiation of free radical polymerization initiated by photoreducible dye sensibilization, especially on description of kinetic schemes, description of reactions which follow the primary process and characteristics of intermediate formed after electron transfer. Considering the interaction between the dye and an electron donor in ground state and after an electron transfer process, dyeing photoinitiators can be classified to three different groups:

1. Photoinitiating donor-acceptor pair with electrostatic interaction in ground state (ground state ion-pair).

2. Photoinitiating donor-acceptor pair without electrostatic interaction in ground state and after an electron transfer.

3. Photoinitiating donor-acceptor pair neutral in a ground state and charged after an electron transfer (radical-ion pair).

Mechanisms and kinetics of polymerization photoinitiation by dyeing photoinitiators are presented.