A new calix[4]triazacrown‐5–derived fluorescence chemosensor (AntUr‐AzClx) at cone conformation was synthesized to afford an effective fluorescent probe, which enables an enhancement in the fluorescence intensity specifically in the presence of Co2+ metal ions as well as a turnoff response for hazardous dichromate anions. 1H‐NMR, 13C‐NMR, ESI‐MS, and elemental analysis techniques were used to characterize the structure of the anthracene‐appended calix[4]triazacrown‐5 (AntUr‐AzClx). The metal ion–binding ability of AntUr‐AzClx was evaluated against Co2+, Ba2+, Ni2+, Pb2+, and Zn2+ ions. On the basis of various metal ion recognition phenomena, AntUr‐AzClx exhibited outstanding selectivity for only the Co2+ ion among other metal ions. Also, the calix[4]triazacrown‐5–derived fluorescence chemosensor showed high sensitivity towards the Co2+ ion with a very low limit of detection (LOD) 0.142 μmol L−1. In addition, anion binding abilities of AntUr‐AzClx against various anions such Cr2O72−, HCO3−, CO32−, NO3−, SO32−, SO42−, N3−, F−, and I− demonstrated that AntUr‐AzClx enables selective and highly sensitive detection of the Cr2O72− anion with an excellent LOD of 4.182 nmol L−1 in DMF/PBS (1/1, v/v; pH: 7.05). Furthermore, the calix[4]triazacrown‐5–derived fluorescence chemosensor displayed a significant sensing behavior to detect the presence of dichromate anions even in real samples.