In this work, we have reported a template-free hydrothermal approach to fabricate highly pure single phase ZnMn2O4 pen-type nano needles assembled with flower type nanostructures. The X-Ray Diffraction, Scanning Electron Microscopy, Energy Dispersive X-Ray spectroscopy, Raman Spectroscopy, Transmission Electron Microscopy, High Resolution Transmission Electron Microscopy, Selected Area Electron Diffraction and UV-visible spectroscopy techniques were used to study the structural and optical properties of Pen-type nanoneedles assembled with flower like nanostrucutres. Single crystalline hetaerolite ZnMn2O4 pen type nanoneedles of flower like nanostructures have an average diameter of 250 nm. Room temperature Raman spectroscopy reveals the four fundamental vibrational modes. Room temperature UV-vis spectrometer was used to determine the transmittance behaviour pen type nanoneedles of flower like nanostructures. Direct optical band gap of 2.19 eV was acquired by using Davis-Mott model. The UV-visible spectrum points out that the absorption is prominent in visible region and transparency is more than 80% in UV region.