His first article was published in Russian Journal of General Chemistry in 1956 and was dedicated to the preparation and applications of silicon carboxylates.

Nikolay Zefirov completed his MSc with honors in 1958, defending a thesis on "Reactions of diene synthesis in the furan series".

Then he continued working as assistant professor in MSU Faculty of Chemistry and graduated his Ph.D "New substitutive addition reactions in the furan series" in 1961.

Ten years later, in 1981, he was appointed a Full Professor of Moscow State University, the Department of Chemistry.

Zefirov made significant contributions to the understanding of Electrophilic addition reactions by establishing the ion-pair mechanism using the example of Thiirane cations.

The “doping effect” can also be observed in more complex cases, such as induction of the skeletal rearrangement reaction in bicyclic compounds.

Moreover, their ability to exhibit strong electrophiles properties and serve as efficient leaving groups was investigated.

[16] He was involved in investigation of various theoretical organic chemistry problems, such as σ-π conjugation,[17] stereochemistry, and conformational analysis.

[19][20] Zefirov is considered a pioneer in computational chemistry in Russia, having made significant contributions to the field.