The photoinitiation abilities of several photoinitiation systems composed of positively charged 3-ethyl-2-(p-(N,N-dimethylamino)styryl)benzothiazolium iodide (dye 1) and 3-ethyl-2-(p-pyrrolidinestyryl)benzothiazolium iodide (dye II) acting as light absorbers, n-butyltriphenylborate (Bo(-)) anion being the electron donor, and alkoxypyridinium (AP(+)) cation acting as ground-state electron acceptor, are compared. Both (Bo(-)) and (AP(+)) in polymerizing formulations were present either as Bo(-) tetramethylammonium salt (TBAB) and AP(+) tetrafluoroborate salt (APTB), respectively, or as an ion pair composed of Bo(-) anion and AP(+) cation (AP(+)Bo(-)). The best photoinitiating ability is observed for the system in which borate anion and pyridinium cation form an ion pair. On the basis of experimental results, it is postulated that an enhancement of photoinitiation ability observed for an ion pair is caused by a specific spatial organization of the reactants allowing the secondary reactions, yielding free radicals, in three-component encounter complex to occur. The mechanism of free radical generation is clarified with the use of laser flash photolysis experiments. Further modification of photoinitiating system concerns a possibility of diffusion elimination at least in one step of the reaction sequence. This was achieved by synthesis of a properly design dye-possessing alkoxypyridinium group. This dye after electron transfer forms radical localized on pyridine nitrogen that fragments forming alkoxy radical and reduced dye. Finally, from a combination of either alkoxypyridiunium or alkyltriphenylborate salts with suitable sensitizer or properly designed dye and alkyltriphenylborate salt, two radicals can be generated per one absorbed photon, thus enhancing the overall polymerization efficiency.