The development of new approaches for the synthesis of new bioactive heterocyclic derivatives is of the utmost importance for pharmaceutical industry. In this regard, the present study reports the green synthesis of new benzaldazine and ketazine derivatives via the condensation of various carbonyl compounds (aldehydes and ketones with the 3-(1-hydrazineylideneethyl)-1H-indole using the grinding method with one drop of acetic acid). Various spectroscopic techniques were used to identify the structures of the synthesized derivatives. Furthermore, the anticancer activities of the reported azine derivatives were evaluated against colon, hepatocellular, and breast carcinoma cell lines using the MTT technique with doxorubicin as a reference medication. The findings suggested that the synthesized derivatives exhibited potential anti-tumor activities toward different cell lines. For example, 3c, 3d, 3h, 9, and 13 exhibited interesting activity with an IC50 value of 4.27–8.15 µM towards the HCT-116 cell line as compared to doxorubicin (IC50 = 5.23 ± 0.29 µM). In addition, 3c, 3d, 3h, 9, 11, and 13 showed excellent cytotoxic activities (IC50 = 4.09–9.05 µM) towards the HePG-2 cell line compared to doxorubicin (IC50 = 4.50 ± 0.20 µM), and 3d, 3h, 9, and 13 demonstrated high potency (IC50 = 6.19–8.39 µM) towards the breast cell line (MCF-7) as compared to the reference drug (IC50 = 4.17 ± 0.20 µM). The molecular interactions between derivatives 3a-h, 7, 9, 11, 13, and the CDK-5 enzyme (PDB ID: 3IG7) were studied further using molecular docking indicating a high level of support for the experimental results. Furthermore, the drug-likeness analysis of the reported derivatives indicated that derivative 9 (binding affinity = −8.34 kcal/mol) would have a better pharmacokinetics, drug-likeness, and oral bioavailability as compared to doxorubicin (−7.04 kcal/mol). These results along with the structure–activity relationship (SAR) of the reported derivatives will pave the way for the design of additional azines bearing indole with potential anticancer activities.