U Zajčevu zborskom stvaralaštvu osobita je uloga pripala Hrvatskom pjevačkom društvu „Kolo” (utemeljeno 1862., djelovalo je do 1948.). „Kolo” je bilo prvo pjevačko društvo kojemu je Zajc posvetio neku svoju zborsku skladbu (U boj!, 1866.). Ona je označila i početak skladateljeve suradnje ne samo s „Kolom” nego i s drugim hrvatskim i inozemnim pjevačkim društvima te potaknula autora na skladanje većega broja skladbi (46) s eksplicitnom posvetom „Kolu”, u čijemu je arhivu sačuvano 99 opusa iz Zajčeva pera. Na temelju uvida u partiture Zajčevih skladbi posvećenih „Kolu” (pretežito a cappella muških zborskih sastava, ali i vokalno-instrumentalnih te jednoga orkestralnog djela) razmatraju se njihove glazbene i tekstne odrednice, vrijeme i kontekst njihova nastanka te Zajčevi višestruki odnosi s „Kolom” – kao skladatelja, dirigenta vlastitih skladbi i djela drugih autora te kao poticatelja i promicatelja zborske djelatnosti. Ona se očitovala u zajedničkim okupljanjima i nastupima „Kola” i drugih hrvatskih pjevačkih društava, a u širem smislu i u promociji i potvrđivanju hrvatskoga nacionalnog identiteta, napose stvaranjem i izvedbom poticajnih domoljubnih skladbi u vrijeme hrvatske kulturne i društveno-političke stvarnosti nakon popuštanja stega Bachova apsolutizma. In Ivan Zajc’s compositions for choirs, the Croatian singing society “Kolo” (founded in 1862, operated until 1948) held a significant role. “Kolo” was the first singing society to which Zajc dedicated one of his compositions, titled To the Battle! (1866), marking the beginning of his collaboration not only with “Kolo”, but also with other Croatian and international singing societies. This inspired Zajc to compose a considerable number of pieces (46) explicitly dedicated to “Kolo”, whose archive contains 99 of his works. Based on the scores of Zajc’s compositions dedicated to “Kolo” (predominantly a cappella pieces for male choirs, but also including vocal-instrumental and one orchestral piece), the author discusses their musical and textual features, the time and context of their creation, and Zajc’s multifaceted relationship with “Kolo”: as a composer, conductor of his own compositions as well as works by other authors, and as a supporter and promoter of choir singing. This commitment was evident in joint gatherings and performances involving “Kolo” and other Croatian singing societies. Furthermore, Zajc’s contributions extended to the broader promotion and affirmation of Croatian national identity, particularly through the composition and performance of inspiring patriotic pieces during the challenging period of Croatian cultural and socio-political history after the loosening of Bach’s absolutism.