<p>Reversible addition-fragmentation chain transfer (RAFT) polymerization, a relatively new method of controlled/living radical polymerization, has attracted scientists’ attention over the last decades due to its simplicity, effectiveness, and high potential for creating complex macromolecular architecture. This article dwells on the issues of pH-switchable dithiocarbamate RAFT agents containing a pyridyl moiety, which can undergo acid-base interactions and modulate the reactivity of the thiocarbonyl group in situ. This capability is essential when aiming to control the polymerization of both more-activated monomers (MAMs) and less-activated monomers (LAMs) using a single compound. This type of RAFT agents has demonstrated excellent control over molecular weight and distribution during the polymerization of monomers of different activity and the ability to synthesize poly(MAM)-<i>block</i>-poly(LAM) copolymers under controlled conditions. In this paper, we report the synthesis of two new N-aryl-N-pyridyl dithiocarbamates and demonstrate how altering the agent’s form (acidic or neutral) and concentration affects the kinetics of the homopolymerization of styrene, vinyl acetate, methyl acrylate, and methyl methacrylate and molecular weight characteristics of obtained polymer. We also report synthesis of polystyrene-block-polyvinyl acetate using synthesized agent.</p>