The use of safe, economic, and efficient initiators in redox free radical polymerization (RFRP) at room temperature (RT) or in cationic polymerization (CP) and as photoinitiators (PI) for both free radical polymerization (FRP) and CP as well as their use for the manufacture of composites are investigated. Remarkably, initiators based on silane/iodonium salt couples are proposed here for their versatility for all the different polymerization modes which is a quite unique feature. The reactions are followed by optical pyrometric measurements, DSC (differential scanning calorimetry), RT-FTIR (real-time Fourier transformed infrared spectrometry), and CRM (confocal Raman microscopy). In RFRP, an adjustable gel time can be controlled between 1 and 15 min by adjusting the concentrations of these redox agents (or even between 2 and 30 min upon addition of stabilizer, e.g., TEMPOL); the storage stability over 5 weeks at ambient temperature and in the dark is excellent. In FRP, up to 80% of reactive function conversion is reached. In CP, the DSC peak drops down from 175 degrees C (in absence of silane) to 113 degrees C. Remarkably, carbon or glass fiber/epoxy resin composites are easily obtained through a dual approach (two steps), i.e., fast photochemical curing for the surface associated with redox or thermal curing in depth.