It is a demand in the modern era of chemical sciences to develop and design new and useful compounds for the service of mankind without the use of methods which are traditional one. Workers were trying to develop and synthesize series of new compounds since past in the laboratories using traditional synthetic methods and they used to check their properties thereafter. This process is time consuming and this lead to synthesis of a large number of compounds. Some recent trends have emerged and developed in the field of designing of compounds which may include microwave synthesis, computer aided designing etc. Out of these methods this presentation/article will focus on computer aided simulation of spectra of compounds on the PC. These computational methods are less time consuming, involve less chances of error, helpful in controlling and causing less pollution and may prove to be helpful in designing compounds with desired properties, in the studies like this. This presentation includes introduction to the computational methods, especially semi-empirical methods. A little bit theory behind these methods and their applications and use of software/ s methods in simulation of spectra of simple organic compounds.