This thesis describes synthesis and biological activity of novel 1,2,3-triazole and heterocycle conjugates. 1,4-Disubstituted 1,2,3-triazole derivatives were synthesized by copper-catalyzed 1,3-dipolar cycloaddition (CuAAC). Synthesis of precursors 6 i 24 used for preparation of acyclic pyrimidine nucloside analogues, and 1,2,3-triazole bis-heterocycles 39–53 and 55–60 were conducted under microwave assisted reactions in order to increase yields and shorten reaction time. 1,2,3-Triazole and 6-phenyl-2(trifluoromethyl)quionline conjugates 75a–75d were additionally synthesized by mechanochemical click reaction and the effect of p-substituent of aromatic azide on reaction course was analyzed. Reaction of cyano substituted derivatives 79a–79i with hydroxylamine in the presence of base resulted in the desired amidoxime substituted heterocycles 80–90, while amidino substituted heterocycles 91–98 were synthesized acording to the Pinner method. Novel O‐alkylated quinoline (104a–104d, 105a–105d) and N‐alkylated (106a, 106b, 107a and 107b) 4‐quinolone derivatives attached to the ferrocene moiety through 1,4‐disubstituted 1,2,3‐triazole were prepared by CuAAC reaction of azidoferrocene precursors and propargylated quinoline derivatives, while quinoline‐ferrocene conjugates 109a–109d with 1,4‐disubstituted 1,2,3‐triazole were obtained by reaction of 4‐(azidoethoxy)quinoline derivatives and ethynylferrocene. All prepared compounds were tested for their in vitro antitumor activities on several human cancer cells and normal fibroblasts and antibacterial activity against selected Gram-pozitive and Gram-negative bacteria. Benzothiazole–1,2,3-triazole–coumarin hybrid 59 showed a strong antibacterial activity against Gram-negative bacteria Moraxella catarrhalis. The interactions with double-stranded polynucleotides ctDNA and dsRNA (pApU) of chosen amidino substituted compounds 91–93, 95 i 96 that displayed strongest antiproliferative activity were studied by using UV-Vis and CD spectroscopy and thermal denaturation experiments. 1,2,3-Triazole tethered quinoline-ferrocene conjugates 106a and 109c displayed marked activities on chronic myeloid leukemia in blast crisis (K562) and Burkitt lymphoma (Raji). Also, compound 109c showed doubled intracellular reactive oxygen species (ROS) generation in Raji cells compared with control.